Prince William is Britain's favourite royal, with the future king beating his wife Kate Middleton and his grandmother Queen Elizabeth II.

The Duke of Cambridge won the poll, run by King's College London and Ispos MORI, with 62 per cent of the vote - the highest approval rating ever gained by a royal since the poll began in 1984.

The Queen came in second with 48 per cent, Prince Harry was third with 36 per cent and the Duchess of Cambridge got 23 per cent, putting her in fourth place.

Results also showed that support for the monarchy is strong, with 90 per cent of people saying they are satisfied with the job the Queen is doing.

Furthermore, 79 per cent said they are in favour of Britain keeping the monarchy and just 16 per cent said they would like it to become a republic.

Roger Mortimore, Director of political analysis at Ipsos Mori and professor of public opinion and political analysis at KCL, said: "This has been a triumphant Jubilee year. After a rocky period in the 1990s, public support for the Monarchy and the Queen now looks as strong as it has been for many years.

"Most of the public now expect the Monarchy to survive well into the future, and that is probably the best guarantee that it will do so."

The levels of support for the monarchy are the highest they have been for 20 years. Over the last two decades, support for the monarchy was between 65 per cent and 75 per cent on average.

Confidence in the royal family is also strong. Sixty per cent of people think Britain will still have a monarchy in 50 years, compared to 25 per cent saying it will not.

While 42 per cent say the royal family will be going strong in 100 years, 38 per cent say it will not survive another century.

Despite these promising figures, many people still have problems with the cost of the monarchy. Over half of voters said the royals receive too much money, compared to 42 per cent who said the amount they are given is adequate.

Even though Prince William is the most popular royal by far, he is unlikely to succeed the Queen as King, bypassing Prince Charles as some have suggested he should.

In June, another Ipsos MORI survey found that the approval rating for Prince Charles had increased.

It showed that the number of people who say Charles should give up the throne in favour of William has dropped to 36 per cent; the lowest level since 2001.