Concern over rising Luton and Dunstable busway costs
Concern has been expressed about the spiralling cost of the Luton to Dunstable guided busway project.
Luton Borough Council and Central Bedfordshire Council's shared contribution has risen from a 4.7% share of £51m, to a 4.7% share of £62m.
Luton Conservative councillor Mike Garrett said he was "shocked" that the council had got into this situation.
Labour-controlled Luton Borough Council said that the project can still be completed for its target cost of £89m.
The £89.2m project, funded by a £80.2m government grant, consists of a mainly guided busway along the disused Luton to Dunstable railway line.
It will serve residential areas in Dunstable, Houghton Regis and the west of Luton, providing connections to the three town centres, Luton Airport Parkway station and the airport.
Both councils need to pay towards the remaining £8.92m initial cost and meet the ongoing revenue costs, capped at 4.7%.
Luton council said the £11m increase in costs, from £51m to £62m, has been incurred by capital overspend and delays to the work caused by heavy rain, plus unforeseen events.
These have included the discovery of additional Japanese knotweed, which is difficult to remove, unknown utility services and contaminated ground.
The council said that the busway team is "continually monitoring project costs to ensure best value for money" and still believes that the busway will be delivered within the budget.
Mr Garrett, the leader of the council's Conservative group disagreed, and said: "We all know that there isn't the finance available now that there used to be years ago.
"To embark on a project which could now lead us into financial ruin, to me it is unthinkable."
Dunstable Conservative councillor Nigel Young, from Central Bedfordshire Council, which is Conservative-run, said the overall scheme costs are "generally as expected".
"We are firmly focused on value for money and are working closely with Luton Borough Council to deliver the scheme within budget," he said.