Campaign for Better Transport chief executive Stephen Joseph has said the impact of successive Government's policies on rail fares has been "appalling" over the past decade.
Today's price hike is the 10th successive annual rise above inflation.
Campaigners have said some fares have increased by more than 50 per cent during that time.
"It's truly shocking that we have deliberately made getting the train to work an extravagance that many struggle to afford," Mr Joseph added. "The time has come not just to stop the rises but to reduce fares."
The Association of Train Operating Companies (ATOC) has defended the way rail companies apply the fare rises that Government policy allows them. While rail fares can only go up by inflation plus 1% that is the average figure which is why some fares have risen by much more today.
Edward Welsh, ATOC spokesman told ITV News: "Just as they might increase them above 4.2% they have to de-crease them elsewhere.
"It's like a traditional pair of kitchen scales. The Government ensures that all the fares come back to 4.2%."
Shadow Transport Minister Maria Eagle told ITV News the rail fare increases represented a broken promise from David Cameron:
"When Labour started doing this ten years ago we weren't in the middle of a double-dip recession with austerity and everybody's living standards being squeezed in the way in which they are now.
"As it became apparent that times were getting tough what Labour did was stop the train companies from charging above the cap.
"So today what people have found going to renew their tickets is that David Cameron promised them they'd be paying no more than 1% above inflation, many people have actually found their ticket price going up by 9%.
Highlighting the fact that Prime Minister David Cameron and Chancellor George Osborne are Old Etonians, transport union TSSA's protest at King's Cross featured a top hat-wearing "ToffsRUs" band.
Waiting for trains at King's Cross station in London today, passengers expressed their anger at the rise.
Outside the station, shadow transport secretary Maria Eagle joined the protest against the high fares.
Some commuters appeared to agree with the protests.
Leeds-bound hairdresser Gavin Lambert, 45, described his service as "rarely on time and often overcrowded", while his friend Kevin Gowland, 46, a musician, said people were taking to the roads as the rail service was "so bad".
How many passengers will pay far more than the headline fare increases?
In terms of costs, thousands of trains are moving in the same direction today... they are getting far more expensive. The headline figure you will read will tell you the rise is 4.2 % for "Regulated fares".
However, Train companies can put some season tickets up by more than that:
A Leeds to Wakefield season ticket is rising 6.16%
Ludlow to Hereford season ticket is increasing 5.28%
London from Ramsgate, Folkestone, Canterbury, Deal and Dover all going up by around 4.8%
Transport Minister Norman Baker told BBC Radio 4's Today programme that the current fare structure was "not ideal", adding that the Government wanted to end above-inflation fare rises as soon as possible:
Forty per cent of fares, roughly, are regulated by the Government and that's a longstanding policy successive governments have had. The other 60% are unregulated and decided by the train companies themselves.
The balance of regulation and which fares are regulated is part of the fares and ticketing review we are now engaged upon.
It's not ideal - there are over 100,000 rail tickets and different prices each year to deal with. It's a hugely complicated issue.So it's important we try to get the best value for the passenger, the best value for the taxpayer and the simplest, (most) transparent system we can, given the need to ensure rail companies can price appropriately to attract people on to off-peak trains which might otherwise be running empty.