Guides who conducted escorted bike rides were "largely idle" during the Tube strike, a union has claimed.
The Transport Salaried Staffs Association called the service, to escort riders into central London from six locations, "pure propaganda".
In total 21 people used the rides and the 18 guides escorted just one ride on 7 September, Transport for London said.
TfL acknowledged the uptake was "low", adding it was one of several alternatives during the strike.
The 24-hour strike, which ended on the night of 7 September, saw members of the Transport Salaried Staffs Association (TSSA) and the Rail, Maritime and Transport union walk out over proposals to cut 800 ticket office jobs.
The groups of three marshals, posted in Swiss Cottage, Clapham Common, Brixton station, Ravenscourt Park, Finsbury Park and Mile End, conducted one ride in the morning to escort cyclists on their own bikes to their workplace in London.
The guided rides were not linked to the cycle-hire scheme, which saw 24,000 journeys during the strike - a 30% increase.
The TSSA said three guides were paid £240 by TfL to escort one cyclist for three miles - Brixton to the Mall.
TSSA leader Gerry Doherty said: "This would be laughable if the situation for Londoners was not so serious.
"This bike guide scheme is pure propaganda. He (Mayor Boris Johnson) would actually save public money by getting rid of the guides and just laying on ordinary cabs for the few who turned up at tube stations last week."
A TfL spokeswoman said: "Guided cycle rides were one of a wide range of measures we took to help Londoners get to work on time during industrial action.
"We acknowledge that attendance levels were low but it was important to offer commuters as many alternatives as possible to help them get to work on time."
The TSSA said that in a 'memo' TfL had advised guides not to criticise the mayor.
It said the memo had advised guides not to say anything which was "pro-strike/anti-Boris".
A TfL spokeswoman said: "It is quite normal for TfL to advise any organisation undertaking work on our behalf, including the company that operated the guided cycle rides, as they will be seen as representing the views of our organisation.
"The 'memo' that the TSSA refer to was simply a short advisory email sent to the director of the company who operated the guided rides on our behalf."