What are Keir Starmer’s biggest issues as he enters Downing Street?

Labour may have stormed to power in a landslide, but Sir Keir Starmer will have no time to celebrate his victory .

The first few days and weeks as prime minister will be a whirlwind that, in hindsight, will make the difficult job as leader of the opposition look easy.

The incoming prime minister’s in-tray will be more daunting than usual because of a rotten economic inheritance – in sharp contrast to 1997, when Tony Blair took over with the economy growing , which eventually allowed him to boost spending on public services.

Sir Keir’s first big task will be to appoint his cabinet and junior ministers. Most of the top jobs are expected to be filled by those who held them in opposition, but there could be some tweaks.

One headache: the number of ministers who sit in the Commons is limited to 95, but 109 Labour MPs were on the front bench in the last parliament. When the Lords is included, Labour had more opposition frontbenchers (146) than there are paid ministerial posts (109).

Will Sir Keir scale back his team and ask many of them to forsake their ministerial salary?

Another dilemma will be whether to appoint as ministers the “retreads” who have returned to the Commons after time out.

The centre of government, 10 Downing Street and the Cabinet Office, will likely be restructured to reflect Sir Keir’s five “missions” and ensure more joined-up government across departments. Figures from business may be appointed to “mission boards” chaired by the PM.

He is likely to create an inner cabinet, or “quad”, including Angela Rayner, Rachel Reeves and Pat McFadden, with other ministers joining it after their briefs are discussed.

Sir Keir has promised to hit the ground running and start addressing voters’ concerns on day one. Labour insiders say they have announcements up their sleeve to show momentum, in a “first 100 days” plan.

They suggest that the big idea will be swift action to streamline planning rules to allow more housebuilding in the green belt, enabling Labour to hit its target to build 1.5 million homes in the five-year parliament.

Other early measures will reflect the incoming prime minister’s modest “first steps”, including plans to cut NHS waiting lists and recruit 6,500 teachers .

Foreign affairs will loom large in the opening days – perhaps larger than Sir Keir might be expecting.

After the traditional phone calls with world leaders, who will be queueing up to congratulate the new PM, he will head to Washington on 9 July for a summit to mark Nato’s 75th anniversary, to be dominated by the war in Ukraine.

There, Sir Keir will be feted by his fellow leaders, who love a winner. He would be wise to enjoy it while it lasts.

The love-in will no doubt continue as Sir Keir is tasked with hosting a meeting of the 47-strong European Political Community at Blenheim Palace on 18 July.

Although it is not an EU institution, the PM is likely to pledge to reset relations and start talking to EU leaders about an ambitious security deal he hopes will extend to economic and border security, and how to reduce post-Brexit trade barriers.

An urgent task will be to finalise the King’s Speech on 17 July, which will set out the government’s legislative programme.

Bills will likely include setting up Great British Energy, a publicly owned clean energy firm; taking the rail network back into public ownership when franchises expire; tackling antisocial behaviour; and reforming mental health laws.

A border security command will be created to show that the government is doing something about the small boats when it formally scraps the Tories’ Rwanda scheme.

Labour will make a start on its plans to enhance workers’ rights, but will also consult with business on the details. Some measures might be delayed, because legislation that sounds easy in opposition can be difficult to draft.

The economy will be centre stage. Rachel Reeves will be the UK’s first female chancellor, and will settle down to plan her first Budget, expected in October. Her big decision after inspecting the nation’s books? Whether to claim a “doctor’s mandate” and raise taxes immediately in the hope of blaming the Tories, or delay any increases in the hope that stronger economic growth makes them unnecessary.

Ms Reeves will also lay the ground for a government-wide spending review, to take effect from next April.

Sir Keir will be keen to demonstrate that he is keeping his promise to return politics to public service after the rule-breaking of the Tory era. He may move quickly to set up an independent ethics commission.

While the new government will probably enjoy a few days of positive headlines, it might not take long for events to blow its “first 100 days” strategy off course.

Ministers will be expected to hold direct talks with the junior doctors in an attempt to end the long-running dispute over their 35 per cent pay claim. Sir Keir has rejected it , but will be keen to avoid the further strikes threatened. However, Whitehall officials are worried about “contagion” if the British Medical Association wins a generous settlement.

Public sector workers have great expectations after years of restraint, and decisions will be due shortly on pay awards, which could cost the government about £6bn.

“Known unknowns” that will make incoming ministers nervous include warnings that the prison population might hit its limit of 88,778. Tackling the backlog in the courts, another inherited problem, could add to the pressure on the prisons without an expanded early-release scheme.

One early crisis could be the collapse of Thames Water, which is on a risk register drawn up by Sue Gray, Sir Keir’s chief of staff, which has been dubbed “Sue’s s*** list” in Labour land.

It is “too big to fail”, so ministers might have to consider temporary nationalisation to maintain supplies to its 16 million customers.

Despite the parlous state of the public finances, Ms Reeves will face many demands for money. Several universities are believed to be on the brink of going bust.

More local authorities might also run out of money; the Local Government Association says councils will have a £4bn deficit over the next two years. Social care is perennially short of resources, and may need a short-term injection until a “fair pay agreement” is introduced. So might the NHS.

The first 100 days will include the summer recess, and Sir Keir will have to accept that his team will need a break to catch their breath in August. But the hard work will resume in the first week of September.