THE £20m refurbishment of Oxford’s tower blocks is expected to start early next year after councillors cleared the way for the project to go ahead.

Last night Oxford City Council approved a £1.75m increase in the scheme’s budget, to meet rising costs it had not expected.

As revealed in May, the work was originally due to begin by spring this year.

But is now likely to take place from January.

It will see Evenlode and Windrush towers in Blackbird Leys, Plowman Tower in Northway, Foresters Tower in Wood Farm and Hockmore Tower in Cowley undergo major improvements.

The blocks date from the mid-1960s and contain 348 flats in total.

In a report to a full meeting of the city council yesterday, project leader Jack Bradley said a contractor could be chosen by August.

Detailed plans are to be drawn up for the scheme by the end of this year.

He said the extra costs were because of demand in the construction industry, as well as the “challenges” of Hockmore Tower – located above Templars Square Shopping Centre, in Cowley – which caused contractors to ask for more cash to do the work.

Mr Bradley added: “Contractors’ submissions for their preliminary costs, which include items such as scaffold, site welfare, transport, compounds and risk items exceeded those envisaged by proven historic data.

“As the tender returns exceed the forecast build spend, the [original budget] of £18.358m is insufficient to deliver the proposed scheme.”

Jean Fooks, Liberal Democrats leader, said the budget increase was not “at all welcome”.

Chief executive Peter Sloman intervened in the discussions and said: “There can be quite a delay between the estimates and the tender. It’s a bit unfair to criticise them for not being able to predict what the market will do.”

The extra cost is being met using “efficiencies and underspends” from the council’s revenue and capital programme last year of about £950,000, using £100,000 from the housing revenue account fund and £700,000 of unused developer contributions for affordable housing, the council said.

It is the second time that the tower block scheme has had its budget increased.

The council has already increased it from £16.6m to £18.36m in July 2014.

Work on the tower blocks will improve the flats and communal areas. Each of the buildings will also be gaining new colourful cladding.

Evenlode and Windrush Towers in Blackbird Leys will be purple, grey and white.

Hockmore Tower in Cowley will be clad in green. Foresters and Plowman Towers will be clad in terracotta.

The council has said it will replace roofs, windows and heating systems, install insulation and communal electrics and refurbish lifts.

Fire safety is also to be improved, new parking put in place and building lobbies given added security.