No one ever said that being in government was easy. But few expected it to be quite as hard as Labour have made it look since the general election.

Keir Starmer today marks 100 days in power, a milestone moment that Liz Truss would have given her eye teeth to achieve.

In keeping with his ‘no drama Starmer’ image, he will spend it in 10 Downing Street rather than his grace-and-favour pile at Chequers. The problem for the prime minister is that his first three months in charge have seen rather more drama than he or his supporters would like.

Any honeymoon the new PM may have expected to enjoy on the back of his landslide election victory on July 4 is now well and truly over.

An opinion poll published last week showed that Labour’s lead over the effectively-leaderless Tories is now down to just one point, with Starmer himself now even more unpopular than Nigel Farage.

A succession of mis-steps, scandals and controversies have dogged his administration, effectively drowning out the work being done to implement Labour’s manifesto and deliver the “change” the party repeatedly promised the country during the election campaign.

“The first 100 days have been a shambles, to be frank,” one senior party figure told HuffPost UK.

“Keir’s come in on a platform of change and as far as the public is concerned they’ve been as bad as the Tories.”

The row over Starmer’s fondness for a freebie – including £20,000 for suits and glasses from Labour donor Lord Alli – has been a drag anchor on No.10′s recent attempts to get back on the front foot.

To try to finally get on top of the controversy, the PM announced earlier this month that he would be voluntarily paying back £6,000 for gifts – including tickets to see Taylor Swift at Wembley – received since the election.

But that seemed to fly in the face of Starmer’s earlier insistence he has done nothing wrong, while also inviting the media to ask other ministers if they would be following suit.

The blame for the payback gambit was laid at the door of Sue Gray, the PM’s chief of staff.

According to one insider, that was “the final nail in the coffin” for the former top civil servant, who was unceremoniously sacked as part of a wider shake-up which saw Morgan McSweeney, Gray’s arch-rival inside No.10, given her old job.

“Sue had to go because it just wasn’t working,” said one Labour source. “Hopefully with Morgan now calling the shots things will calm down and the government can actually get on with doing what it was they were elected to deliver.”

The Irishman, who co-ordinated Labour’s successful election campaign, has wasted little time in letting it be known that there will be plenty of changes to the way things are done in Downing Street from now on.

At the most recent political Cabinet meeting, McSweeney set out to Starmer’s top team what Labour has already done – including setting up GB Energy and kick-starting the re-nationalisation of the railways – to emphasise that it’s not all doom and gloom inside No.10.

“We’ll see more drive from the centre,” one of his allies told HuffPost UK. “We’ll be able to get across the PM’s aims and objectives in a way we haven’t so far.

“Morgan is just a much more political operator and he’ll be able to get the stuff Keir wants to do into the bloodstream of Westminster and the government as a whole.

“He also has a much stronger relationship with special advisers because he led the election campaign and people know what he wants to do. It will be quite a big change.”

Starmer himself is known to be deeply frustrated at the stuttering start his administration has made – another fault which has been laid at the door of Sue Gray, who was given the task of preparing Labour for government.

“I don’t think the plan for government was good,” one No.10 adviser said. “If it even exists, I’ve never even seen it. That made it all harder than it needed to be. That first 100 day grid of announcements just never really existed.

“Despite that there is good legislative stuff being done that will build up into the change that people will actually feel. As we get into the next 100 days and the next 1,000 days that will be the focus on the stuff we want to do.”

As well as the row over freebies, the decision to axe winter fuel payments for 10 million pensioners has also presented Labour’s opponents with an open goal.

Despite the government’s protestations that they inherited a £22 billion black hole in the public finances from the Conservatives, the majority of voters believe that was the wrong choice at the wrong time.

The Budget on October 30 – which Starmer has already warned will be “painful” for the country – is now even more important than it already was.

One the one hand, it presents Labour with a golden opportunity to reclaim the political narrative and get back on the front foot.

However, anything which resembles George Osborne’s “omnishambles” Budget of 2012 will simply re-affirm the belief among many voters that this is a government that is out of its depth.

One Starmer aide insisted the prime minister is managing to remain calm despite the storms buffeting his government.

“He knows that politics goes in ups and downs,” he said. “We had the same thing in opposition, but he’s never been someone who takes the highs or the lows too dramatically. He won’t be too worried about individual polls.”

A cabinet minister said that whatever the challenges of government, they were nothing compared to the frustration of opposition.

He also insisted that with the Conservatives about to lurch to the right under either Robert Jenrick or Kemi Badenoch, there was still plenty for Labour to be positive about.

“It’s great to be back in power,” he said. “Yes, we’ve had a few rocky headlines, but there have also been announcements on things like foreign investment, renters’ reform and how we’ll make work pay.

“The Tory leadership race also shows that they have learnt nothing from the beating they took on July 4.”

But as Keir Starmer chalks up his first century of days in No.10, he knows the pressure is now on to turn the warm words of the election campaign into concrete achievements.

Keir Starmer will chalk up 100 days as prime minister next Saturday.

He will do so without his now-former chief of staff Sue Gray, who today carried the can for the chaos which has engulfed the government since Labour’s landslide election victory just three months ago.

Although the official line from No.10 was that Gray resigned, HuffPost UK has learned that the PM ultimately decided that she had to go.

A senior Labour source said: “Change was needed. Things weren’t working properly. Better to do it now than let it drag on.”

It is understood that the final straw was the decision, blamed on Gray, that Starmer should pay back around £6,000 for hospitality and gifts he has received from Labour supporters since becoming prime minister.

The move appeared to be an admission of guilt by the PM, and inevitably led to other ministers being asked whether they would be following suit. So far, none have done so.

“That was the nail in the coffin,” said one senior Labour figure.

Another insider added: “This is Keir’s usual pattern – something drifts on for a while and then he acts hard and ruthelessly.”

Gray has also been blamed for the new government’s complete failure to set the political weather since July 4.

As Starmer’s chief of staff in opposition, it was thought that she would use her vast experience from her time in the civil service to meticulously draw up and then implement Labour’s plan for government.

“People are annoyed about the lack of preparation,” said one Downing Street source. “It’s actually unforgivable.”

Last month’s Labour conference – which Gray did not attend – was supposed to be a reset moment.

But the row over freebies for senior Labour figures has refused to go away, completely overshadowing the government’s attempts to get back on the front foot.

Meanwhile, rumours about the bad blood among Starmer’s officials – in particular the long-running feud between Gray and the PM’s chief adviser, Morgan McSweeney – continued.

She acknowledged the damage that was doing in her resignation statement, in which she admitted that the speculation about her own position had become “a distraction to the government’s vital work”.

To add insult to injury for Gray, McSweeney has replaced her as chief of staff as part of a major shake-up inside No.10.

One government aide said: “Morgan’s the political equivalent of Yoda. He will be outstanding.

“He ran one of the most disciplined, strategic and successful election campaigns in history. People said we could never win the party back from the hard left – Morgan did it.”

Gray has not disappeared completely, and her new role as Starmer’s envoy for the nations and regions will be an important one, albeit far less influential than her previous job.

The Tories – many of whom have never forgiven Gray for her partygate report which ultimately led to Boris Johnson’s removal from office – can hardly believe their luck.

“Sue Gray was brought in to deliver a programme for government and all we’ve seen in that time is a government of self-service,” said a Conservative spokesperson. “The only question that remains is who will run the country now?”

With a parliament-defining Budget barely three weeks away, Starmer needs to quickly show that he is the one calling the shots. His decision to oust Sue Gray is his first step towards doing just that.