Transport councillors will be encouraged to act as “mystery shoppers” as a condition for getting free passes to travel on trains and buses.

Members of West Yorkshire Passenger Transport Authority will be asked to file reports on punctuality, cleanliness, attitudes of staff and the behaviour of passengers.

One source said the Unite union, which represents transport workers, would not be hostile to the move because many bus and train operators including First already used their own mystery passengers to monitor driving standards and staff’s conduct.

Details of the plan emerged as members of the passenger transport authority’s audit and governance committee approved plans for all 22 Metro councillors, including representatives of Bradford Council, to be given free Metrocards.

The cards, which give unlimited travel across West Yorkshire, were available free to Metro members until 2003 when an external auditor drew up a Public Interest Report that said free cards to members was “illegal”.

But the auditor recently indicated that its stance had changed because it recognised that, in their role as ambassadors of public transport, it was important that Metro members had the opportunity to use buses and trains.

Bradford Councillor Chris Greaves, chairman of the passenger transport authority, said information learned on such journeys could assist in formulating transport policy.

He said: “The outcome was in favour of reintroducing cards for members, but this was not for any pig-in-the-trough reasons.

“It should actually produce a saving because, at the moment, a member can claim expenses if they go to Leeds on the train or bus for a meeting.

“Each Metrocard issued will cost the authority £262, whereas one journey to Leeds costs me a fiver and I have to go three or four times a week for Metro meetings, so you can already see the savings.”

Members who receive a Metrocard will not be able to submit expense claims for travel within the county on public transport after 9.30am.

Occasional private use of the Metrocard is permitted and Metro said the Members Allowances Scheme would be amended to reflect this.