John Profumo, the Tory minister forced out following a notorious 1960s sex scandal, was for years in correspondence with a glamorous German spy, sending her endearing notes on Commons notepaper, according to newly declassified MI5 records.

The politician met the model Gisela Winegard at Oxford in the 1930s before she went on to work for German intelligence in wartime Paris, and kept in touch until at least the 1950s.

Her file released at the National Archives in Kew also includes claims made by her husband that the couple had separated because he found compromising letters to her from Mr Profumo.

At the height of the Profumo Affair in 1963, MI6 sent a letter and files to MI5 investigations head Arthur Martin about Profumo’s contacts with Winegard, maiden name Klein, and outlining her exploits.

The MI6 officer, Cyril Mackay, wrote: "Although it is not particularly relevant to the current notorious case, Geoffrey thought you might like to have for your files the attached copy of a report from our representative [redacted], dated 2nd October 1950, which makes mention of an association between Gisela Klein and Profumo which began ca 1933 and had apparently not ceased at the time of this report."