The website running a fundraising campaign to raise money for the family of murdered policeman Pc Keith Palmer is refusing to waive its five per cent fee, The Telegraph can disclose.

The fundraising page set up by JustGiving for the Metropolitan Police Federation has raised over £670,000 by Friday night.

This means that JustGiving - which pockets 5p of every pound donated - is likely to receive around £33,500 in administration fees.

The website donated £10,000 to the fund when it started, which would give it a £22,500 profit so far.

So far more than 27,000 donors, many of them anonymous, donated to the fund and chose to leave moving message on the site as tributes to Pc Palmer who was knifed to death in the grounds of Parliament by a terrorist on Wednesday.

One donor, who gave £30, wrote: “You gave your life serving your country and its people. I am one person in a sea of grateful individuals”.

Another, who gave £20, said simply “deepest sympathy”. A third donor who offered £10 to the fund wrote: “Condolences”.