Bus workers are to lobby Parliament next week to press for the right to be regarded as key workers for housing schemes.
Those recognised as key workers, such as nurses, police officers and teachers, get access to a wider range of affordable housing schemes and mortgages.
According to the Transport & General Workers' Union (T&G), government figures on earnings and average house prices show the extent of the housing problem.
With the average house price in Greater London at £293,349 and the median weekly earnings for a bus driver - including overtime, bonuses and shift premiums - being £496.50, drivers are effectively priced out of the housebuying market.
The T&G, the largest trade union representing bus drivers in London and the South East, said this was "proof if proof was needed" that the key worker scheme needed to take in bus workers as it was almost impossible for them to get on the property ladder.
Tom Scanlon, T&G senior regional industrial organiser, said without bus workers, London and the South East would come to a halt. "Bus workers have ensured that the people of London and the South East can go about their daily business during emergencies," said Scanlon.
"But like many other key workers, they are being forced out of their communities because they cannot afford to buy or rent homes in their neighbourhoods."