Passengers will not be enticed back onto buses without tough changes to the way the industry is regulated, says the senior traffic commissioner for the UK.
First Bristol says it is working to solve its problems
Buses accounted for 40% of the travel market in the 1950s - but this has now dropped to just six per cent.
The government annually ploughs millions of pounds of taxpayers' money into improving services - and aims to increase passengers by 12% over the next 10 years.
But Phillip Brown, who has the power to ultimately scrap a bus company's licence for bad performance, says operators can threaten to cut vital services if he imposes financial penalties on them.
"I think that certainly a large bus company can always turn around and say: 'Okay, if that's your attitude, we're stopping, we're pulling out and you'll have no buses at all.'
"And there's always the possibility of them saying, 'We're going to put our fares up.'
Mr Brown said that the 1986 deregulation of the bus industry had made it difficult to enforce standards across the country - as commissioners were no longer able to set fares or routes.
His comments came as part of a File On 4 investigation which uncovered the bus industry's poor reliability and safety failings.
Earlier this year, Mr Brown ordered a public inquiry into the operation of First Bristol, part of the huge First Group empire.
He fined them £96,000 after discovering that 20% of buses were running late - and another 11 % were running early.
But Mr Brown said the local authority shared the blame for the services not running to time for failing to implement bus priority measures - such as bus lanes, bus-friendly traffic lights and road improvements.
"It's very frustrating when local authorities don't seem to be prepared to commit to getting more people out of cars - for whatever political or financial reasons.
"I'm a bus passenger - so I can speak from that at first hand.
"Unless you've got bus priority measures you'll never get a bus running on time in a city centre and that's the bottom line."
Tony Grayling, of the Institute of Public Policy Research, said the lack of partnerships between local councils and bus operators was putting the government's bus network expansion plans under threat across the UK.
"In most areas of the country, local authorities are wary about the way bus operators behave. I think there are quite a few examples where new fleets of buses have been promised which haven't been delivered.
"But equally I can see why bus operators are going to be reluctant to invest and improve those services when they can't be sure that the local authority will deliver on its side of the bargain."
File On 4: BBC Radio 4, Tuesday 9 August, 2005 at 2000 BST and repeated on Sunday 14 August, 2005 at 1700 BST.