Hard-hit rail commuters will today learn just how much more they will have to pay for their season tickets from next year. Analysts warn fares could rocket by more than 8pc on some routes, while Friends of the Earth fear it could drive communters back onto the roads.

The bad news will come in today's July inflation figures which are used to determine the following January's annual rise for regulated rail fare, which include season tickets.

Today both the region's major rail firms said they would not be confirming exactly how big an increase commuters would face until later in the year.

National Express East Anglia, which runs services on the Norwich to London Liverpool Street line, along with trains between Norwich and Great Yarmouth, and Norwich and Cambridge, said most increases would be around the 8pc mark.

That means a season ticket from Norwich to London would increase from �6,540 to �7,063; Diss to London from �6,060 to �6,544; Norwich to Cambridge from �3,680 to �3,974 and a season ticket from Great Yarmouth to Norwich from �1,432 to �1,546.

First Capital Connect, which runs services between King's Lynn and London, said it would reveal next year's fares in November or December.

A season ticket between King's lynn and London King's Cross currently costs �4,360, while a season ticket from Ely to London costs �3,924. An 8pc rise would see them increase to �4,708 and �4,237 respectively.

Norfolk's MPs have recently joined forces to campaign for improvements to rail services between the county and the capital.

There are reliability issues on the Norwich - Liverpool Street line, while overcrowding is a major problem on the King's Lynn - King's Cross route.

To make matters worse for those travelling on increasingly-crowded trains, the Government has changed the fare-rise formula for 2012.

This means regulated fares will no longer rise by the RPI inflation rate plus 1pc but will, from January 2012, go up by RPI plus 3pc.

With the July 2011 RPI rate likely to be around 5pc, this means the January fare rise will be around 8pc. But as train companies are allowed to make the 8pc an average figure, some season tickets could go up by much more than that.

Members of Fair fares Now and the Campaign for Better Transport demonstrated against the fares hike at London's Waterloo Station.

The campaign is also supported by the RMT transport union which today published a report saying rail privatisation had 'bled �6.6bn out of the rail industry since 1997'.

The RMT-commissioned report by research company Just Economics also said that the future 'bleed' would amount to around �6.7 bn over the next 10 years.

RMT general secretary Bob Crow said the Government was 'forcing through inflation-busting fare increases and savage cuts to maximise private train company profits'.

Campaign for Better Transport's public transport campaigner Alexandra Woodsworth said: 'Affordable rail travel is vital for passengers, for the environment and for our workforce. These massive fare rises will be a disaster for people already struggling with rising costs, and risk pricing those on lower incomes out of jobs in our major cities.

'Our demonstration is sending a clear message to Government that the country simply can't afford fare rises on such a punitive scale. It's time to burst the bubble on inflation-busting fare hikes.'

But David Mapp, commercial director at the Association of Train Operating Companies, said: 'We know that these are difficult financial times for many people.

'The Government has decided that many fares need to rise above inflation for the next three years to help pay for more trains, better stations and faster services.'

He went on: 'Increasing the money raised from fares will mean that taxpayers contribute less to the running of the railways, while ensuring that vital investment can continue. All additional money raised through the change to RPI plus 3pc will go straight back to the Government.

'The industry is working with the Government to cut the cost of running the railways, building on the progress that has already been made.

'A more-efficient railway will help to limit fare rises in the future, and offer better long-term value for money for the taxpayer.'

Friends of the Earth transport campaigner Richard Dyer said: 'It's a national scandal that train fares are to increase above inflation. Passengers in the UK already pay some of the highest fares in Europe.

'Price hikes send out the wrong message to commuters seeking a greener alternative to driving. The Government should encourage people to travel by train by capping rail fare rises and by upgrading the rail network to make services more reliable.'