Talks to pave the way for free bus travel across Oxford for the over-60s have started.

On Thursday the city's two main bus companies -- Stagecoach and Oxford Bus Company -- will receive a letter from the city council explaining how they will be reimbursed for the scheme, which starts in April next year.

The trouble is no one has been able to calculate how many extra journeys will be taken once the scheme comes into force.

In Oxford the current concessionary charge for the over-60s is 30p for a single journey and 40p for a return with about 2.25m journeys undertaken each year by 20,000 people at a cost to the city council of £1.1m.

However, the nearest calculation of what it may cost has been from a firm of independent consultants who reckon a totally free scheme will set the city council back about £2.2m a year.

The bus companies currently provide the Town Hall with information on journey patterns each quarter and are reimbursed accordingly.

But as yet the city council has received no indication as to how much of a share of a national pot of £350m it will get to fund its concessionary scheme.

Graham Smith, the city council's transport and parking manager, is meeting Department for Transport bosses in London today to discuss the situation.

He said: "We don't know how much money we are going to get, but we want to pay as little as we can, the bus companies want as much as they can and the customers are somewhere in the middle.

"We may go for a system that benefits us and the bus companies may object to it.

"The worst-case scenario is that it costs us £2m but nobody knows how many extra journeys there will be -- and that's our nightmare.

"Everything is up for changing and until I get to London I don't know what's going on."

What remains unclear is how those wanting to travel across district council borders will be charged. Someone living in Oxford but wanting to visit a friend in Abingdon would only receive free travel as far as the Vale border from where they would have to pay a reduced fare.