The call to return the EU's multi-starred flag could cause considerable embarrassment for the party leadership, which faces a right-wing backlash over Europe at the party's annual conference in Blackpool.
Hugh Dykes, former chairman of the Conservative Group for Europe, said the EU flag did feature on the platform a few years ago but "mysteriously disappeared" with the "sad resurgence of nationalism and xenophobia in our great party".
Restoring the EU flag would highlight the Tories' commitment to Europe and John Major's "fervent wish for us to be at the heart of Europe", he added in a letter to Sir Basil Feldman, chairman of the National Union of the Tory Party at Conservative Central Office.
Mr Dykes, the chairman of the Commons' European Movement, also sent his demand to Brian Mawhinney, the Conservative Party chairman.
Mr Dykes said he was shocked by the disclosure in the Independent of 130 conference resolutions tabled on Europe, many supporting the approach adopted by the right-wing Tory Euro-sceptics.
"Many of my colleagues, including myself, were shocked by the large number of motions. It is essential for the conference organisers to ensure we have a positive debate on Europe," he said.
Mr Dykes said he believed that many of the conference resolutions were part of an orchestrated campaign by Euro-sceptics. However, John Redwood, the right-wing challenger for the Tory leadership, who will be speaking at fringe meetings at the conference, denied there was a Euro-sceptic plot behind the resolutions.
"I know a number of constituencies that did put in resolutions that you would say were sceptical and I've asked them whether anybody put them up to it. They've said no," Mr Redwood said on GMTV.