The Mayor of London is alerting business and political leaders in the Liverpool City Region that they face the prospect of not regaining its aviation route to the UK’s only hub airport even if a third runway at Heathrow is given the go-ahead.

The number of British cities served by Heathrow has plummeted by more than 60 per cent from 18 routes in 1990 to just seven today. Liverpool lost its connection to Heathrow in 1992.

On Tuesday, the Mayor wrote to eleven regions and more than 480 key businesses around the country to highlight the fact that the Airports Commission itself has forecast that an expanded Heathrow would accommodate even fewer domestic routes – reducing the number of British airports connected to a UK hub from seven to four.

This finding makes it increasingly unlikely that Liverpool John Lennon Airport will regain its connection to an expanded Heathrow.

The multi-billion pound expansion of Heathrow would also only deliver a maximum of 12 new long-haul destinations, according to the Airports Commission – that’s fewer than the number of destinations we should be serving in China and India alone.

Hub airport connections are vital to the economic prosperity of Britain’s regional cities as they rely on connections to and from hub airports for international trade, tourism and for foreign investment.

The Liverpool City Region is home to the UK’s second largest regional economy, worth £121bn and supporting more than 252,000 businesses.

Key sectors in the Liverpool City Region such as advanced engineering, financial and professional services, and creative enterprise would be boosted by the global access that only a UK hub can provide.

Aviation experts agree that cities without hub connections with network airlines can become invisible to those seeking to do business. Since 1990, 11 UK airports have lost air service connections to the Heathrow hub: Birmingham, Durham Tees Valley, East Midlands, Guernsey, Humberside, Inverness, Isle of Man, Jersey, Liverpool, Newquay and Plymouth.

The seven British cities which have retained a direct air service connection to Heathrow –Aberdeen, Belfast, Edinburgh, Glasgow, Leeds, Manchester and Newcastle – have all seen a reduction in the number of flights to Heathrow. On average the number of daily flights these airports operate to Heathrow has almost halved.

The Mayor of London, Boris Johnson, said:

“Having connections with the UK hub airport is hugely important for Liverpool and the wider region. Those connections allow businesses to trade and secure investment across the globe. But the truth is that Heathrow has been failing our regions for well over a quarter of a century and quite staggeringly the Airports Commission’s own analysis shows that the construction of a third runway only worsens the situation. That is not how you rebalance the economy and spread prosperity across the UK.

“The only long-term solution that would enable British businesses to compete on a level playing field with our European competitors is to build a four-runway hub airport, and the only logical location for that airport is to the east of London.”

The erosion of access to the UK’s hub airport has left Britain’s regional cities with poorer connectivity to London. But perhaps more importantly Britain’s regions have also seen their global connectivity fall behind competing cities in mainland Europe.

Statistics from the Official Airline Guide’s 2015 summer schedule for Europe show Heathrow served just 174 international destinations. Meanwhile Frankfurt served 259 international destinations, Amsterdam Schiphol 254 and Paris Charles De Gaulle 241.

Britain needs a hub airport with four runways in order to compete with the four runway airports in Europe, such as Frankfurt and Paris Charles De Gaulle, which have overtaken Heathrow. However, the Airports Commission has explicitly ruled out a fourth runway at Heathrow, not least in recognition of the increased air and noise pollution over London, and even goes as far as to propose legislating against it ever being built.

Cities in emerging markets not served by Heathrow but served by its European competitors with four or more runways include: Nanjing, Hangzhou, Chongqing, Wuhan, and Shenyang in China; Dar es Salaam in Tanzania; Dakar in Senegal; Panama City, and the South American capitals of Santiago, Caracas, and Montevideo.

The Mayor is also calling for people to write to their local MP and ask whether the Government has given them any assurances that routes to their region from Heathrow will be protected or restored by the construction of a third runway after decades of cuts.

A suggested letter is already available for people to view at: www.london.gov.uk/flightsletter