Ron Yates, 84, a veteran of the North Africa campaign in World War II, told the AJ he would sit in front of bulldozers to halt plans by the Duke of Westminster's developer Grosvenor to flatten the Brutalist giant.
Hailed as a 'stunning example of 1960s co-ordinated transport planning' by the Twentieth Century Society, the bus station will be pulled down under current proposals - masterplanned by Farrell's - to regenerate the centre of the Lancashire city.
Last month an agreement was signed between Grosvenor and Preston City Council which will pave the way for 85 new shop units, 400 homes and a 12-screen cinema on the central Tithebarn site. A planning application is expected to be submitted early next year.
However Yates, the joint co-ordinator of the Save Our Bus Station campaign, is determined to defend the bus garage, which was designed by Keith Ingham and Charles Wilson of BDP and the council's own engineer EH Staziker.
The ex-army sergeant, whose son worked on the construction of the building's concrete sections, believes he can muster up a brigade of more than 50 supporters to physically block the bulldozers.
'It's a perfect bus station,' said the pensioner. 'I've been all around the country and there are none as good as ours.
'It would be a loss to Preston - it just fits in. I like the look of it'.
Yates has previous experience of demonstrating, having staged anti-nuclear sit-ins at Aldermaston in Berkshire.
The pensioner was also involved in trying to get the five-storey interchange listed, a move that prompted a delegation from Preston council to travel to Westminster to successfully block the attempt.
But Yates is undeterred. He added: 'There is so much feeling against this happening and we are doing our best to stop it.'