MOMENTUM for approval of the extension to Nottingham's tram network appeared unstoppable less than a month ago.

But today city Labour MPs claimed opposition from Boots to a proposed tax on workplace parking spaces could block plans for the two new tramlines.

They said the company's lobbying had now left the future of links to Wilford and Clifton and Beeston and Chilwell in doubt.

A ministerial decision on whether the tram routes – NET Phase Two – would go ahead was expected in March, followed by a decision on the workplace parking levy (WPL), the tax to help fund the new lines.

But intense pressure from Boots has led to a "wobble" among decision makers at the Department for Transport (DfT) in their commitment to the WPL, which could cost Boots more than £1.5m a year.

The DfT is even believed to have suggested an alternative tram funding package to the city council in return for them ditching the tax, because they thought it would not raise enough money in the long term.

A Westminster source said: "Things are taking longer than anyone thought they would.

" It turns out those at the top of DfT are beginning to wobble because of pressure from Boots; the company is dead against the levy.

"An idea was floated from the Government side about providing some sort of alternative funding, but without the WPL it would have meant covering the tram's costs for the next 20, 30 or 60 years.

"The sums needed simply aren't there and so the idea was knocked on the head."

Peter Gibson, of Alliance Boots, has dismissed any suggestion the company was putting the extension of the tram network at risk.

He said the workplace parking levy was the wrong method of paying for it and the company believed the DfT did not have enough money to fund it.

The Government has encouraged councils to contribute their own funding for local transport schemes.

The city council wants to charge companies £185 a year for every parking space from 2010, rising to £350 per space within five years.

With 4,500 parking spaces at its Beeston headquarters, this would leave Boots with an annual bill of just over £1.5m by 2015.

City Labour MPs have warned that if the Government refuses to let Nottingham bring in the WPL, the new tram line would be impossible to fund.

They claim £168m plans to widen the A453 would also have to be shelved.

Nottingham East MP John Heppell said: "I don't think Boots realised their objections could not only stop the WPL, but would halt the tram and the work on the A453.

"Boots have been asking for improvements to the A453 for years and now it's them who might inadvertently stop it. The simple fact is that there is no plan B. It's every bit of the transport plan – WPL, the tram, the A453 – or nothing."

Nottingham South MP Alan Simpson said NET Phase Two would include a park and ride site at Clifton, where much of the extra traffic from a widened A453 could stop, with drivers taking the tram – across Wilford Toll Bridge – to the city centre.

He said: "Without the tram, and the park and ride, all the extra traffic would be pushed on to Clifton Flyover, which is a terrible bottleneck.

"Boots are being dumb about this; they've been saying they lose millions because their vehicles are always stuck in traffic (on the A453).

"Now because they don't want to pay a parking fee they will end up in an even bigger jam."

Mr Gibson said: "The money raised by the levy is only a small part of the total cost.

"It is more likely the Department for Transport is taking a fresh look at the finances because of how much the scheme is costing and whether it can find the money in these financially-strapped times."

Mr Gibson also warned the workplace parking levy would make firms reconsider whether they wanted to move into Nottingham in the future, and could make companies already here think about moving elsewhere.

He strongly urged the Government and city council to take a fresh look at other options to fund lines two and three of the tram, such as a road user charge to encourage car users to look at other forms of transport.

Mr Gibson also pointed out Boots was an early supporter of the concept of a tram network in Nottingham 20 years ago and contributed to the cost of a report assessing its viability.

Coun Graham Chapman, city council deputy leader, said: "What Boots has to understand is what is at stake.

"That is the tram, railway station improvements, improvements to the A453 and the Medilink buses linking the hospitals and buses to employment sites, including Boots, which the WPL will pay for.

"This is a whole house of cards and Boots has not understood that. These are very high stakes."

A spokesman from the DfT said he was not able to comment on the claims the DfT did not have the funding to pay for the tram extension.

The DfT said consultations on the WPL were going to plan.

A spokesman said, however, that the more "representations" that were lodged on the plan the longer it would take officials to sort through them.