At a Parliamentary reception organised by High Speed Rail Industry Leaders, HS2 Minister Nus Ghani said: “I urge all of you to work closely with MPs so they understand how important this project is and the benefit it will bring to our country.”

She spoke of ‘naysayers’ within the ‘Westminster bubble’, who she said should travel to the Midlands and the north of England to see first hand how transformative the £50Bn scheme is expected to be.

She described High Speed 2 as a regeneration project that will connect towns and cities and rebalance the economy. “It will be the backbone of our country’s rail network.

“It’s big and its bold and it requires all of us to work together because we are not just building a railway, we’re building a vision and I really want this next year to be a year when all of us go out and sell the idea and vision behind HS2.”

Also addressing the reception, Labour’s Shadow Transport Secretary Andy McDonald said: “This project chimes very strongly with Labour’s economic vision and our pledge to ensure all regions of the UK get the investment they deserve.”

But he added: “Where there are people across the country and Members of Parliament who are expressing some reservations and concerns, we have got to double down and make sure we are addressing those in very particular detail.

“That has got to be everybody’s task, to make sure the case continues to be made because the naysayers have raised their heads in recent months.”

Andy McDonald also said the scheme will need to feed into wider regeneration ambitions in the towns and cities that it will connect, and align with much needed upgrades to other parts of the railway network.

Addressing rail professionals in the room, High Speed 2 strategic director for stakeholder engagement Tom Kelly said: “HS2 is more than a railway – by joining up Britain we will build a fairer, more balanced economy.

“But we can only deliver that purpose if we work together. We need to deliver this in an innovative way that gives good value for the taxpayer and convince them that they are getting good value.”

• Meanwhile it has emerged that reductions in the scope of High Speed 2 – including lowering train speeds – may have to be considered to keep the project within budget and on time.

Leader of the House of Commons Andrea Ledsom sent a letter to HS2 chief executive Mark Thurston seeking clarity on statements made to the All Party Parliamentary Group for Rail in November.

He was said to have suggested a number of potential cost cutting measures including lowering the speed that trains will operate at by around 50km/h, reducing the number of trains from 18 per hour to 14, and changing from a slab track to a ballast track.

In her letter the MP for South Northamptonshire wrote: “My constituents are naturally concerned that changes to the project could undermine the business case, negatively affect the benefit-cost ratio, and reduce the value for taxpayers’ money.”

Mark Thurston responded: “At the meeting I responded to direct questions from members about what could be done to change scope in an effort to reduce cost.

“However I was also clear that HS2 Ltd is working to the scope and budget of the project which the Government has set, and for which detailed debate in Parliament had taken place.

“If at some point in the future we are instructed to consider any of these options, then more detailed work on the effect of such changes would of course take place.”