Whether new letters or correspondence involving Hubble changes this assessment remains to be seen.

FORBES: Science and Censorship

The museum stresses the value of the newly-bought letters as "genuine correspondence between artists".

BBC: A new book of Van Gogh's letters is to be published in 2008-9

There are around 4, 500 personal and academic letters including his full correspondence with Darwin.

BBC: Alfred Russel Wallace's 19th Century letters go online

The cache of letters apparently features convivial correspondence between MI6 officials and Mousa Kousa, then the head of Libya's intelligence operations.

ECONOMIST: MI6 and the army accused: Long shadows | The

Correspondence, even letters of great import, has been signed by secretaries and by machine.

FORBES: All the Presidents' Pens

He said the letters showed the prime minister was "in extensive correspondence and contact with the Hindujas over a wide range of issues, and so was his government".

BBC: Hinduja 'cover up' claimed

Thousands of Wallace's letters have been put online for the first time, including correspondence with Darwin about evolution by natural selection.

BBC: Why does Charles Darwin eclipse Alfred Russel Wallace?

At the urging of some in the HD DVD camp, the European Commission has sent letters to many of the Hollywood studios asking them to produce any correspondence relating to their backing of the Blu-ray format.

ENGADGET: European Commission looks into Blu-ray studio agreements

The letters are kept in the collections of 100 institutions worldwide and the Wallace Correspondence Project has so far digitised about 95% of them.

BBC: Alfred Russel Wallace's 19th Century letters go online