The 717th anniversary of the Battle of Stirling Bridge, which saw an outnumbered Scottish army led by William Wallace and Andrew de Moray defeat forces from the south, takes place on September 11. The Guardians of Scotland Trust, which aims to promote the roles of the two men in the key confrontation, has now crossed swords with the Heritage Lottery Fund (HLF) after it refused the grant for a public art project.
They say the scheme is in jeopardy as match-funding will now be withdrawn.
Sir Tom, who has written a number of publications on history and is director of the Scottish Centre for Diaspora Studies at Edinburgh University, said: "The Battle of Stirling Bridge is second in importance only to Bannockburn in the Wars of Independence. It is imperative that the location should therefore be marked in a suitable fashion."
The HLF insisted there was stiff competition for the grant and it had lost out to a better bid.
Campaigners are now urging Lottery players to give up on their hopes of becoming a millionaire for a week and donate the £4 spent on the purchase of two tickets for the draw towards the proposed scheme.
John Robertson, of the Guardians of Scotland Trust, said: "We are asking the public to send a signal to the National Lottery by choosing not to buy a lottery ticket and send the money to us instead.
"We cannot make you a millionaire in cash terms but you will contribute to a public artwork which will last for generations."
A spokesman for HLF said: "There were also a number of other applications which offered better value for money in a highly competitive round of decision-making."
The trust, which made up of historians and politicians from a number of parties, has received a £173,000 pledge from Creative Scotland, towards the cost of the proposed project.
However, it says, this must be match-funded.
The site of the proposed artwork is thought to be where Wallace and de Moray stood shoulder to shoulder before the battle commenced. De Moray died of the injuries he received in 1297.
Visitors currently have very few markers to the site.
The trust said it has received support to set this project up from Historic Scotland, Stirling Council, local community groups, academics, historians and local businesses.
Mr Robertson, who is also part of a group called Andrew de Moray Project, said he felt the project was viewed as too political in the run up to next month's independence referendum.
He pointed out it was a heritage initiative with no interest in political point-scoring.
He added: "This project aims to present the first physical commemoration to Andrew de Moray anywhere in the world.
"It appears HLF Scotland do not want to fund a project which might be construed as political and in so doing, have placed an important heritage project in jeopardy."
Mr Robertson, added: "Creative Scotland require all earmarked funds are matched as soon as possible and in time for a decision by the Board in September 2014.
"If Creative Scotland opt to withdraw interest on the basis of lack of match funding without support of HLF, the Guardians of Scotland Trust will be forced to consider possible closing down of this project."