The chairman of a watchdog committee today said he feared the delayed Bradford City Park project could now be millions of pounds overspent.

Andrew Mallinson, chairman of Bradford Council’s regeneration and economy overview and scrutiny committee, has demanded answers when it meets next month.

The Telegraph & Argus exclusively revealed last week that the Council’s £24.4m flagship scheme next to City Hall will miss its scheduled opening date in September and will instead open in November, although it will not be finished until January.

The ambitious project includes a mirror pool containing more than 100 fountains, making it the biggest man-made urban water feature in the UK.

Last minute changes have been brought in to cut costs which include not building a separate events control room which will now be incorporated in the main pavilion, and cancelling “a piece of public art”.

It is understood behind the scenes negotiations are going on between Bradford Council and the contractor Birse over the costs of the scheme, which was largely funded by the sale of Leeds-Bradford Airport.

The Council would not comment on the specifics of the overspend preferring instead to reiterate its earlier statement: “Delays usually involve extra resources. We are working within a contract and for commercial confidentiality reasons we are therefore unable to outline how much we expect those to be at present. We understand the need for transparency and we will make the details available as soon as we can.

“We have adjusted the design and adjusted the scheme – including removing the events control room which will now be incorporated in the main pavilion, and a piece of public art – to manage costs.”

But Councillor Mallinson (Con, Craven,) said: “There has been an overspend and the figure that is being bandied around the corridors of City Hall is £4m. I find it very strange that the Council can find ways to hide behind such an overspend.

“I can’t see any commercial confidentiality issues around this at this stage whatsoever. The people of Bradford, in hard economic times, need to know who signed off this overspend and they need to be brought to task.”

Coun Mallinson said he has asked officers to explain themselves at next month’s scrutiny committee meeting.

Council leader Ian Greenwood told the T&A: “Discussions about any issues surrounding the cost of construction are still commercially confidential and it would be inappropriate for anyone on any side to comment further at this time.”

Councillor John Cole (Lib Dem, Baildon), a member of the overview and scrutiny committee, said: “This is a very worthwhile project and the budget over-run is unfortunate but it has been explained. I know Council officers have worked hard to minimise the overspend and they have been quite robust with contractors.”

The Council has blamed the delays on adjustments to the design once construction work began causing, for example, earthworks to be pushed into the winter which has exacerbated the problems. The severe winter conditions also caused some delays, as did unforeseen events like the English Defence League protest.

Asked by the T&A to explain exactly how the EDL protest contributed to the delay, Barra Mac Ruairi, the Council’s strategic director for regeneration and culture, said: “In the weeks leading up to the EDL and anti-fascism demonstrations (in August 2010), City Park construction workers had to be pulled off scheduled tasks to make the site secure on the advice of police and our emergency planners.

“This included removing more than 300 tonnes of excavated earth, installing hundreds of additional double layered fencing panels, backfilling all open excavations and removing machinery and any potential objects, from stones to signs, that could have been targeted by protesters.

“It then took a number of days after the demonstrations to return the site to normal.”