John Prescott was the pugnacious political bruiser who became an indispensable figure in Sir Tony Blair’s New Labour project.

For more than a decade, the ex-merchant seaman provided a crucial link with the party’s working-class roots as Sir Tony’s reforming drive led critics to accuse him of abandoning socialism altogether.

Notoriously short-tempered, as deputy prime minister he famously brawled with a protester who struck him with an egg while out campaigning during the 2001 general election.

He had a stormy relationship with the press who dubbed him “two Jags”, and who mocked his at times jumbled syntax in statements and interviews.

He nevertheless emerged as a key mediator in the turbulent relationship between Sir Tony and chancellor Gordon Brown, which dominated the politics of the time.

But after leaving office along with Sir Tony in 2007, he became increasingly critical of the New Labour legacy, denouncing Britain’s involvement in the Iraq War and backing Jeremy Corbyn.

Born in Prestatyn in Wales on May 31 1938 the son of a railwayman, John Prescott left school at the age of 15 to work as a trainee chef and then as a steward on the Cunard Line.

As well as becoming an accomplished amateur boxer, he was also becoming active in the Labour Party and the National Union of Seamen.

He was one of the “tight-knit group of politically motivated men” denounced by prime minister Harold Wilson for organising a seamen’s strike in 1966.

Despite incurring the Labour leader’s displeasure, he nevertheless secured the party’s nomination for the safe seat of Hull East, which he won in the 1970 general election, having stood unsuccessfully in Southport four years earlier.

Initially he embraced many of the positions of the Labour left – including its opposition to Britain joining the European Community.

By the early 1980s however he had moved away from the hard left and in 1983 he backed Neil Kinnock to succeed Michael Foot as party leader.

Initially rewarded with a place in Mr Kinnock’s shadow cabinet, they fell out when he mounted an unsuccessful challenge to deputy leader Roy Hattersley for his job in 1988.

After Mr Kinnock and Mr Hattersley resigned following Labour’s general election defeat in 1992, Lord Prescott stood again for deputy leader only to lose again – this time to Dame Margaret Beckett.

He nevertheless struck up a strong rapport with new leader John Smith, helping him deliver his reforms to the party constitution with a barnstorming conference speech.

When Mr Smith died suddenly in 1994, Lord Prescott ran for both leader and deputy leader.

While easily beaten by Sir Tony for the top job, he reversed his previous defeat at the hands of Mrs Beckett to secure the position of deputy.

It marked the start of an at-times uneasy alliance as Sir Tony embarked upon the reform programme which was to propel Labour to a general election landslide three years later in 1997.

At times Lord Prescott looked distinctly uncomfortable among the spin doctors and other trappings of New Labour – once famously mocking Peter Mandelson as a crab.

However his rough-hewn manner and trade union roots were seen as an essential foil to the Oxford-educated Sir Tony amid considerable mistrust within the movement over his public service reforms.

In office, he was rewarded with the new “super ministry” covering the environment, transport and the regions as well as the title of deputy prime minister.

In that role he was credited with a number of successes, including helping to negotiate the international Kyoto Protocol on climate change and creating regional development councils as well as reforms to the transport system.

However, he was also involved in a series of clashes with the press who gave him the nickname “two Jags” – a reference to his official Jaguar and his own car – while urging the public to take fewer journeys by car.

Meanwhile his ambitious aim of developing an “integrated transport policy”, embracing all areas of his department’s remit, proved a stretch too far and after the 2001 election it was broken up leaving him with oversight for the regions.

It was during the 2001 campaign that he had his infamous encounter with protester Craig Evans, who struck him with an egg, prompting Lord Prescott to retaliate with a straight left to the jaw.

The incident however did no damage to the party at the polls, while Lord Prescott joked that he had simply been obeying Sir Tony’s orders.

“He told us to connect with the electorate, so I did,” he said.

During Labour’s second term, Lord Prescott increasingly found himself drawn into the role of peacemaker between Sir Tony and Mr Brown, amid the chancellor’s growing frustration at the unwillingness of his erstwhile friend to step aside.

After Labour was re-elected in 2005 with a reduced majority, those tensions became more pronounced.

Lord Prescott meanwhile suffered personal humiliation in April 2006 when the Daily Mirror disclosed that he had been conducting a two-year affair with one of his secretaries. His wife, Pauline, was said to have been devastated.

A poor showing in the local elections the same month saw him stripped of his departmental responsibilities – although he retained the title of deputy prime minister, along with his full cabinet salary and two grace-and-favour homes.

Further embarrassment followed when pictures emerged of him playing croquet on the lawns of his Dorneywood country house on a Thursday afternoon when he was supposed to be “running the country”.

It prompted a contrite Lord Prescott to deliver an apology to Labour’s annual party conference, telling delegates “I let myself down, I let you down,” and that he would be standing down as deputy leader when Sir Tony resigned.

Following Sir Tony’s departure from No 10 in May 2007, Lord Prescott announced he would not be standing again as an MP, and following the 2010 general election he was introduced to the Lords as Baron Prescott of Kingston upon Hull.

In 2012, he made an unsuccessful bid to become the first elected police and crime commissioner for Humberside, while in 2015 there was a brief spell as adviser to Labour leader Ed Miliband.

Away from Westminster, he published his memoirs, in which he revealed he had suffered from the eating disorder bulimia nervosa, brought on, he believed by stress of life at the top of politics.

He ceased to be a member of the House of Lords in July after suffering from ill health.

Official records show he had only spoken once in the chamber since suffering a stroke in 2019 and had not voted since February 2023. He died following a battle with Alzheimer’s.

Lord Prescott is survived by a widow and two sons.