David Cameron controversially used the backdrop of Downing Street to make a direct plea to older people not to vote to leave the European Union.

The Prime Minister asked voters to think about their children and grandchildren before they made an “irreversible” decision.

But he was accused of abusing his position by making the appeal live on television from outside No 10.

Tory MPs protested that he was breaking strict rules that surround elections.

The UK Government is officially in ‘purdah’ and banned from making any announcements that could sway voters.

The rules also state that Government property should not be used for campaigning.

Leading Eurosceptic Tory MP Bernard Jenkin said the Prime Minister's speech was "certainly a breach of the spirit of purdah".

He added: "Ministers aren't meant to use public funds or public resources during the purdah period.

"It can be argued it doesn't apply to his own residence but I would have thought use of Downing Street facilities is a breach of the spirit of purdah.

"He would not do that during a general election."

Mr Cameron's former aide, the pro-Brexit campaigner Steve Hilton, suggested that Mr Cameron had "wheeled out" for the television cameras to distract from an earlier row, in which No 10 was forced to deny his claim that civil servants admitted four years ago that the Tory leader’s immigration pledge was "impossible" to meet.

In the brief address, which lasted just a few minutes, Mr Cameron did not mention migration.

He said that "future generations" would be "hit hardest" by the economic impact of leaving the EU.

"For you, for your family, for the future of our country, vote Remain," he said. Opinion polls suggest that older people are both more likely to vote and more likely to want to leave the EU than younger generations.

Mr Cameron told them: "I want to speak very directly to those of my generation and older. I know Europe isn't perfect, believe me I understand and I see those frustrations. I feel them myself.

"That's why we negotiated and enhanced our special status - out of the Euro, keeping our borders, not involved in ever closer union. We have the best of both worlds.

"So as you take this decision, whether to remain or leave, do think about the hopes and dreams of your children and grandchildren. They know their chances to work, to travel, to build the sort of open and successful society they want to live in rests on this outcome.

"And remember, they can't undo the decision we take. If we vote out, that's it. It is irreversible. We will leave Europe for good.

"The next generation will have to live with the consequences far longer than the rest of us."

On Thursday, he told them, "it will just be you in that polling booth... taking a decision that will affect your future, your children's future, your grandchildren's future".

He said: "Our economic security is paramount... if we leave we will put it at risk.

"That is a risk to jobs, a risk to families, a risk to our children's future and there is no going back."