Her representatives approached Margaret Thatcher to ask for a meeting as part of a bid to enhance her claim to be the ‘heir to Ronald Reagan’ and prepare to challenge Mr Obama.

And Lady Thatcher has agreed to see Mrs Palin, who stood as the Republican vice-presidential candidate in 2008. A spokesman said: ‘We had an informal approach asking if Lady Thatcher would meet Mrs Palin if she comes to Britain and we said yes.’…

One individual involved in the talks about the visit said: ‘Palin’s people haven’t said anything about meeting Cameron. Their main interest is getting a picture of her with Lady Thatcher. I’m not sure they know who David Cameron is.’