David Cameron has admitted holding a referendum on Britain's EU membership was the right thing to do.

The former Prime Minister defended his decision to call the vote whilst speaking to an audience in the Ukraine, saying the EU had been 'poisoning' British politics for years.

He added: 'I made a promise to hold a referendum. It was the right thing to do.'

He made an indirect reference to his Labour predecessors by saying they had promised referendums and never delivered them.

His comments came after his successor, Prime Minister Theresa May, triggered Article 50, the mechanism for any country to leave the EU under the 2007 Lisbon Treaty, last Wednesday.

Cameron promised to enshrine a commitment to hold a referendum on Britain's EU membership in the 2015 Conservative Party manifesto.

This policy followed his 2013 Bloomberg speech announcing he supported the idea after UKIP were stealing huge swathes of Conservative support prior to his statement.

Once he won the 2015 General Election, he sought to renegotiate Britain's EU status.

But his efforts failed to persuade the majority of electors who voted in last year's vote that Britain was 'stronger in the EU.'

After 17.4 million people voted for Brexit on June 23rd last year, he declared his resignation in the face of defeat.

'The result is not the result I sought'

Reflecting upon his humiliation on Wednesday, the former Tory leader said: 'The result is not the result I sought.'

However, contradicting the campaign message he promoted last year, the former Witney MP confessed he was always a Eurosceptic at heart.

He added: 'I have never liked the European flag or the European Parliament.'

After trying to justify his reasons for leading the Stronger In campaign that supported Britain's EU membership, the former Tory leader said: 'We were in the EU for reasons of utility rather than emotion.'

He also praised Mrs May's decision to follow through with the will of the British people.

'Threatening the EU'

Despite this, the current Prime Minister's letter has been condemned as a 'threat' after she stated Britain would resort to World Trade Organisation rules if the EU fails to agree on post-Brexit trade and security arrangements.

Work and Pensions Secretary Damian Green said on Newsnight the idea of the letter being a threat 'is a misunderstanding.'

But the President of the European Council, Donald Tusk, has since backed down, saying he will hold trade talks in parallel with Brexit if there is 'sufficient progress' on the divorce negotiations.

Nonetheless, Spain has since threatened to use sovereignty over Gibraltar as a bargaining chip over a future trade deal.

'We are not leaving Europe'

Speaking in Kiev, the fallen premier said it is vital Britain and the EU continue to cooperate on defence and security in a post-Brexit world.

He added: 'Whilst we are leaving the European Union, we are not leaving Europe.'

The former Remain PM has been hosting after-dinner talks since resigning as premier and an MP last year.