Scores of travellers say the trouble-hit Plymouth to Penzance train rarely runs on time - and is often cancelled altogether.

Now a group of fare rebels are refusing to buy a ticket for their journey to work in the morning, until First Great Western gets the service back on track.

"It's gone past the point of frustration - now it's become a comedy," remarked commuter Bex Ferriday as the 'cancelled' sign flashed up on a digital screen at St Austell station shortly before 8am on Monday.

For Ms Ferriday, a teacher trainer at Cornwall College who was heading for an appointment at the Camborne campus, it was a familiar scenario. In the past seven weekdays, the key commuter train ran late on five occasions and was twice scrapped.

Jeremy Palmer, who travels from his home at St Austell to his job with Defra in Truro, said: "The service has become so appalling lately, we've refused to pay."

St Austell commuter Steve Jenkins, who works at the Cornish Studies Library in Redruth, said the service was causing havoc for countless travellers. "I know of people who have received disciplinary letters for repeatedly arriving late at work," he said.

Mr Jenkins, who has chronicled a record of the 8.10's performance stretching back five months, handed his dossier to the Cornish Guardian following the latest cancellation. We passed his figures to the train operator on Monday.

On Tuesday morning, with the service running around 21 minutes late, passengers on the Penzance-bound train found a letter on their seat. Signed by Andrew Haines, chief operating officer for First Great Western, it read: "Over the last few weeks, we've not been giving you the service you deserve, and the level of disruption many of you have experienced is simply not good enough.

"I want to say sorry for our recent poor performance and the inconvenience it has caused."

He blamed a variety of difficulties including signalling and track problems, over-running engineering work by Network Rail, freight and passenger line failures, trains without enough carriages and crew shortages.

Mr Haines outlined a £750 million investment over the next 18 months to make the region's track and signals more reliable.

He told passengers they would be entitled to compensation if they had experienced delays to their journey of more than an hour.

"In addition to this, and to thank you for your patience, I'd like to offer season ticket holders compensation equivalent to two days' travel in rail travel vouchers," added Mr Haines.* For compensation details, log on to fgwfeedback@firstgroup.com