Sir Keir Starmer faces another first-time challenge this week.

Still just months into the job, the prime minister will be delivering his first speech to the annual Lord Mayor’s Banquet in the City of London on Monday.

It will be a rare chance to see the Labour leader in white tie and tailcoat in the glistening historical setting of Guildhall, surrounded by the rich and powerful. Unless of course, Sir Keir follows his Labour predecessor Gordon Brown and tries to dress down.

Sir Keir is bound to dwell on the economy, the poor inheritance he believes he has received from the Conservatives, and his determination to stay the course set in the recent budget.

By convention, however, the prime minister’s Guildhall speech focuses on foreign policy and Britain’s place in the world.

The grandees in the dining hall, and the waiting world beyond it, will be listening out for how Sir Keir’s thoughts are shaping up since his election victory and after the crash course in international diplomacy he has undertaken in very uncertain times.

Foreign affairs matter for PMs – and the UK

The UK did “take back control” with the Brexit referendum vote. This country is now an independent entity outside the big power blocks of the United States, the European Union, China and Russia, and unaffiliated with the rest of the world in Africa, Asia, the Middle East and Latin America.

The UK must try to navigate a successful future for itself at a time when there is a widespread populist impulse to put national interests first ahead of any multinational obligations.

The new prime minister has been an easy target for all the time he has spent travelling abroad. The critics who suggest he should have stayed at home need to say which of the official engagements he should have cancelled.

Do they really think he should have abandoned the UK’s place at the top table for meetings of the United Nations, the G7 summit of Western democracies, the G20 gathering of the world’s biggest economies or COP29 on climate change?

Are they saying he wasted his time forging inaugural bilateral contacts with key allies including presidents like Macron, Biden, Trump, Zelenskyy, and Scholz.

Debutant prime ministers are often surprised by the amount of time they have to spend on foreign affairs. As they become more experienced, most of them realise it is one of the most important aspects of heading a government.

Diplomacy also has attractions for them personally. It is an area of policy where they deal with equals, other foreign leaders, and can take decisions – at the most extreme staying in and out of wars – without having to manoeuvre around colleagues and parliament at home.

Most cabinet ministers and MPs are rightly preoccupied with domestic issues such as health, education and welfare. This leaves a prime minister and their advisers plenty of leeway for exercising statecraft.

Envoys matter almost as much as the top job

The personal relationships prime ministers and their envoys develop with their foreign counterparts can have a significant impact on the national interest.

Non-elected officials or representatives, operating in so-called “back channels”, are likely to matter more and have more direct influence than in other policy areas.

Consuelo Thiers, a political psychologist at the University of Edinburgh, studies leadership approaches to international relations.

She believes: “Starmer’s personality is characterised by a high belief in his ability to control events, a strong need for power, and a complex approach to decision-making.”

So far he has moved deliberatively, gaining experience and avoiding black-and-white positions. He is also slowly assembling a team of advisers which seems to hark back to the New Labour government of Tony Blair and Gordon Brown.

The top appointment is Jonathan Powell as national security adviser. Powell was Tony Blair’s chief of staff throughout his decade in power. He was a risk-taking participant in the backchannels which resulted in the 1998 Good Friday Agreement in Northern Ireland. Before that, he was a career British diplomat, serving in Washington DC.

Starmer previously hired Powell on a one-off basis to negotiate a settlement over the future of the Chagos Islands. That agreement handed sovereignty over the islands to Mauritius but kept access for 99 years to the Diego Garcia military base for US forces.

But the deal is now in danger of unravelling because of elections in the US and Mauritius. Weeks before he officially starts being national security adviser, Powell is shuttling between capitals again trying to find a compromise.

Marco Rubio, the US president-elect’s nominee for secretary of state, has said the arrangement would “provide an opportunity for communist China to gain valuable intelligence on our naval support facility”.

Meanwhile, the new Mauritian Prime Minister Navin Ramgoolam also wants to review the deal.

The Islands will only be the first example of the big power rivalries between US and Chinese interests which Powell will have to grapple with on Starmer’s behalf.

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Reliable team could help repair EU relations

The UK’s other essential relationship is with Europe.

Starmer has reaffirmed that there will be no return to freedom of movement, the single market or a customs union with the EU.

But, unlike his Conservative predecessors, he has energetically pursued warmed relations with European and EU leaders.

Where the Conservatives set up a Department for Exiting the EU, Starmer has established an EU directorate in the Cabinet Office, separate from the Foreign Office, under the minister Nick Thomas-Symonds.

The government is now advertising for a senior official to reset relations with Brussels. Michael Ellam, who moved with Gordon Brown from the Treasury to Number 10, is expected to get the job, according to The Financial Times. Ellam is a veteran heavyweight civil servant with many connections in the EU having worked as chair of the EU financial services committee during the UK’s membership.

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Olly Robbins and Antonia Romeo, the two front runners to become the next cabinet secretary, also both have significant foreign policy experience, in Brussels and New York respectively, although Starmer may choose one of the two other domestic-focussed civil servants from the four-person shortlist.

His newly appointed director of policy in Downing Street is Liz Lloyd. She was Powell’s deputy in the Blair government and has since worked as an international investor and banker in Africa.

It’s less likely, but some have been advising the prime minister to take up Nigel Farage’s offer to be a linkman to the Donald Trump administration.

As he looks out across the candelabras of Guildhall on Monday, Sir Keir Starmer may only hint at his worldview in the reassuring knowledge that he is quietly putting together a reliable team who will watch his back and look out for the national interest in the unavoidable backchannels of diplomacy.