Papers released under the freedom of information law yesterday showed the scale of political interest in the 1997 death of Princess Diana.

The revelations do not give much fuel to conspiracy theorists but do show how the cost of her funeral grew as public grief mounted.

One official wrote that the £5m bill for the service still only amounted to "scarcely a deck on the royal yacht".

The papers also reveal correspondence between then Downing Street communications chief Alastair Campbell and Press Complaints Commission boss Guy Black on the row over whether Tony Blair wanted a bigger role in the Queen Mother's funeral.