COMPLAINTS about abuse of Scotland's controversial free bus travel scheme have increased more than six-fold over the past two years, The Herald can reveal.

Transport Scotland, the Government agency that runs the £187 million scheme, investigated 208 cases of "over-staging" last year – up from 31 cases in 2009.

The scam involves over-60s or disabled passengers who are entitled to free bus trips being given a ticket for a longer journey than they in fact made.

The abuse means firms can claim a higher rate of reimbursement than they are due from the Scottish Government.

It is one of several fraudulent practices suspected of costing taxpayers millions of pounds in the early days of the scheme, which was set up in 2006.

However, Transport Scotland has claimed success with sophisticated anti-fraud measures since 2009, which it says have enabled officials to gain a far more accurate picture of the trips passengers are making. In addition, passengers are reporting rogue operators in growing numbers.

The installation of automated ticketing machines on buses, the last of which went live in December 2010, has provided data on every concessionary journey made in Scotland, replacing crude survey techniques.

Together with back-office data analysis technology, this has made it much easier to identify passenger journeys that have been recorded inaccurately or fraudulently.

The agency has recouped nearly £50,000 as a result of criminal prosecutions against companies suspected of defrauding the scheme.

However, the overall savings to the taxpayer, as reported by The Herald last year, is estimated to be £24m a year through cutting out fraud, misuse and red tape.

Ronnie Mellis, operations manager for concessionary travel at Transport Scotland, said: "The difference is almost immeasurable from the point at which we started. In 2006, claims [for reimbursement] were made in writing by bus operators and to check them we had to send survey staff out to count the number of concessionary bus passengers.

"Now, a single passenger complaint is enough to tip us off. Or we can get a tip-off from the daily data analysis of journeys."

The 208 complaints investigated in 2011 relate to cases "of substance" rather than those in which a passenger has complained about a ticket issued legitimately but where the destination is different from the actual stopping point, Mr Mellis said.

He welcomed the rise in complaints by the public, saying this reflected greater awareness of potential misuse of the scheme and a greater focus on protecting public funds.

The agency is now planning to set up a dedicated phone line, expected to go live later this month, to make it easier for the public to report cases of suspected abuse.

The number of free bus journeys has dropped by 15 million, or 9%, from a peak of 159 million in the 2007/8 financial year to 2010/11 following the implementation of more accurate means of recording journeys.

But it is unclear how much of this decline is due to eliminating inaccurate and fraudulent claims and how much is due to a slump in overall bus travel.

The number of bus journeys, not including concessionary travel, declined by 14% over the same period, largely due to a rise in unemployment.

Last month, operators warned that fares will be pushed even higher this year as the scheme runs out of money.

Operators issued the warning after complaining about a failure to reimburse them for millions of journeys, as demand for free travel exceeded funding. They claim this has left them facing an expected shortfall of more than £7m for the next financial year.

The Confederation of Passenger Transport UK, representing more than 1000 bus firms, said fare hikes and cuts to services were on the cards as members could no longer afford the losses.

It is calling for a full review of eligibility to contain the Scottish scheme's costs, which have spiralled since it was introduced in 2006.

The anti-fraud drive was welcomed by the Confederation. George Mair, its director, said: "We're fully supportive of Transport Scotland's efforts to catch anyone who abuses the concessionary travel scheme. At the end of the day, we want to see money going where it rightly should go."