Northumbria Police has confirmed the incident has been referred to the Independent Police Complaints Commission due to the contact between officers and the man before he died.
The air ambulance was called and the man was given CPR treatment by officers until paramedics arrived. Despite efforts to save him, he was pronounced dead at the scene. The area around the cliffs has been cordoned off while an investigation is carried out.
The police watchdog has been informed after a man was found dead at the bottom of cliffs moments after escaping from a police vehicle.
Northumbria Police said the man's body was discovered at the bottom of Marsden Grotto cliffs in South Shields just after 1am.
The force had been called to the area at 12.34am after receiving a report of a group of people fighting in the car park of the Marsden Grotto pub.
They attended and arrested a man in connection with the fight and he was placed inside a police vehicle.
Liberal Democrat leader Nick Clegg has told Daybreak his party did not "contest seriously" last week's by-election in South Shields, in which its candidate topped only the Monster Raving Loony Party.
The Deputy Prime Minister said: "There was a by-election just a few weeks ago in Eastleigh which we spectacularly won. Some by-elections parties do well in others they don't contest seriously. That was clearly the case if you contrast Eastleigh with South Shields."
Mr Clegg also said his party would not "lurch (to the) right or left" after its disastrous local election results, which saw it lose 124 council seats and comfortably trail UKIP.
Labour's election co-ordinator Tom Watson said his party enjoyed a good night in the local elections and South Shields by-election.
Speaking to the BBC Radio 4 programme, Mr Watson said "We had a good result on what we have seen so far, to get 50 per cent of the vote in South Shields, to win back the mayor in Tyneside, to make progress in the Westminster battleground seats within counties is good for us.
"In the Westminster battleground seats, places like Harlow, Hastings, Stevenage, Cannock, the Westminster seats we lost in 2010 and we need to win back in 2015, they are coming back to Labour in quite big numbers."
The MP for West Bromwich East said Labour leader Ed Miliband had been consistently told by voters that they felt a sense of "powerlessness" when it came to politics and its ability to change their lives.
"At the heart of this is economic failure, they feel the Government plan is not working and they feel the job of the Labour Party is to convince people there is a better way, that we can address this squeeze on living standards and give people more hope," he said.
The Lib Dems have told me things are pretty horrific for them in South Shields, with it looking like the 'third party' vote has all gone to UKIP.
The turnout in the Parliamentary by-election, sparked by former foreign secretary David Miliband's resignation, is 39.3%.
The only "real choice" for voters at the forthcoming local elections is between the Conservatives and Labour, David Cameron has said.
In a direct attack on Labour leader Ed Miliband's policies, the Prime Minister said "the scale of the challenge is actually laid bare today because this is the day when the leader of the Labour Party is turning left.
"More spending, more borrowing, more debt - that is what he's calling for, more of all of those things that got us into this mess in the first place."
Mr Cameron said the Conservatives were "fighting for the pound in your pocket" adding it was "a moral imperative" to keep council tax down.
"We're fighting to keep it there because we get something, it is your money, not our money and not Government money."
TV comic Lee Nelson intends to stand for Parliament in the by-election for David Miliband's former seat of South Shields.
The character, created by funnyman Simon Brodkin and who has his own BBC3 series, intends to contest the election on 2nd May after handing in his nomination papers this morning.
Earlier this month Brodkin escaped prosecution following his arrest in March for sneaking on to the pitch and training with the Manchester City team prior to a Premier League match.
Nelson, standing for Lee Nelson's Well Good Party read out a speech on the steps of the Town Hall in South Shields, delivering a "17-point manifesto for a Well Great Britain" with a series of eye-opening policies, including issuing each child with lottery scratch cards at birth.
He added: "David Cameron, George Osborne, Boris Johnson - I wasn't educated at Eton or Oxford. In fact, I wasn't educated at all. It's time to give the posh the push. And let Lee be your leader for a well great Britain."
The by-election triggered by former foreign secretary David Miliband's departure from the Commons is set to be held on May 2.
Labour sources said Mr Miliband would formally vacate the South Shields seat on Monday, and the writ would then be moved for the contest.
Emma Lewell-Buck was selected as the party's candidate for the safe seat earlier this week.
Labour leader Ed Miliband has said British politics will be a "poorer place" following his brother David's decision to step down as an MP.
The former foreign secretary, and the elder of the Miliband brothers, announced this morning that he will be moving to New York to become head of a US-based charity.
ITV News political correspondent Alex Forrest reports:
Sunderland football club has said David Miliband will continue as vice chairman and non-executive director, despite quitting as a Labour MP for South Shields: