Property leaders have joined forces to write to the government urging Rishi Sunak not to abolish the remaining northern section of HS2.

Bosses at some of the UK’s largest property firms are among a list of around 80 cross-industry business leaders to pen a letter to the prime minister highlighting the benefits of the high-speed rail line, connecting London Euston to Birmingham, with links to both Manchester and Leeds.

The first part of the line, between west London and Birmingham, is already under construction, but the current projected cost for the section is almost £45bn, well above the £30bn estimate in 2010 of what it would cost to build the whole network.

However, there is speculation that Sunak will scrap plans to build HS2’s second phase from Birmingham to Manchester due to estimated cost rises.

A cost estimate which formed part of a briefing for the PM and chancellor Jeremy Hunt indicated that £2.3bn has been spent on Phase 2 of the high-speed rail project – which takes the route north of Birmingham to Crewe in Phase 2a and on to Manchester in Phase 2b. The same cost estimate says the government would save £34bn if the project were to be shelved.

Property leaders that have signed a letter urging Sunak not to abolish scheme include: Nick Walkley, principal and UK president at Avison Young; : British Land chief executive Simon Carter; Gary Neville, owner of Relentless Developments; Chris Oglesby, chief executive of Brutnwood; Andrew McFarlane, head of UK regions at Colliers; Henry Boot chief executive Tim Roberts; and Patricia Moore, UK  managing director of Turner & Townsend.

In the letter, the property leaders and other industry bosses, academics and regional business organisations warned the prime minister that any plans to water down the scheme would damage Britain’s reputation as a place to do business.

Melanie Leech, chief executive at British Property Federation, said: “A decision to scale back or abandon the next phase of HS2 would be a huge disappointment to the North and a step backwards for the Levelling Up agenda.

“Connectivity is one of the key drivers of economic growth and HS2 would not only support the cities on the line but also the wider regions they serve. Public sector investment in infrastructure of this scale also acts as a magnet for private sector investment, bringing huge additional benefits in growth and job creation.

“Renewed uncertainty only undermined those plans as well as the long-term health of the construction sector, and its ability to invest in skills, innovation and capacity. This ‘stop-start’ approach has a knock-on impact on the northern economy; there are clear, long-term benefits to the greater connectivity HS2 can deliver and we hope the government will re-affirm its 100% commitment as soon as possible.”

The chief executive London Property Alliance, Charles Begley, also wrote an open letter to transport secretary Mark Harper highlighting the success of the Elizabeth Line in boosting business in the capital.

He said: “The clouds of uncertainty around the delivery of HS2, especially the critical Euston connection, undermines business confidence and the economic, environmental and social potential of this important national infrastructure project.

“The new Elizabeth line stations, serving as a major interchange for other lines, have significantly accelerated the recovery in the retail economy, particularly in areas like Covent Garden, Oxford Street and even emerging submarkets such as Paddington.

”Since 2012, there have been 171 hotel openings, 2,666 new food and beverage outlets and 12 museums opening within a mile of the stations.

“London’s businesses and high streets can expect to benefit in similar ways from the added connectivity through a Euston HS2 terminus, with growth prospects also extending to Birmingham and beyond, if the project is delivered in full.”