People protested at about 20 stations

The day of action was organised by Bristol-based passenger group More Train Less Strain (MTLS).

It issued travellers with fake tickets which read "Worst Late Western" and Class Cattle Truck standing room only.

Some passengers have been allowed to travel using the tickets while others have been made to buy valid tickets.

Commuters are protesting against overcrowding, high prices and unreliable services.

Eoin O'Keeffe, 28 and Lizzie Walkley, 26, said they had been advised to buy a valid ticket but then were let through the barriers and told they may be questioned again.

But Geoff James, 34, was turned away at the gate while trying to use a fake ticket to get to Yate.

'No prosecutions'

"I was refused entry... the service is rubbish. They won't provide a decent service at a decent price," he said.

Mike Holmes, Temple Meads station manager said names and addresses of passengers holding the fake tickets were being taken.

"We will be writing to these passengers to tell them what we will be doing with the service," he said.

He also said there would be no prosecutions from action on Monday morning.

This contradicted information given earlier by Andrew Griffiths, regional manager of FGW.

He said: "People are allowed to protest but we can't compromise safety.

Some passengers with fake tickets were let through, others not

"We will take the names and addresses of everyone without a valid ticket and decide later on whether to prosecute."

The fares strike is the second held by MTLS.

In January 2007 around 2,000 commuters from Bristol and Bath took part.

This time, the group said protests were also taking place at 20 stations including Yate, Frome, Highbridge, Trowbridge and Warminster.

FGW has blamed ageing rolling stock and staff shortages for many of its problems, but said the issues were being addressed.

In a statement issued later, FGW said: "We have monitored today's claims of a fares strike and, on trains and stations across the network less than 100 people refused to pay - out of 100,000 daily passengers and 1,350 daily services.