The UK Government-backed Davies Commission has rejected London mayor Boris Johnson's proposal of a new four-runway airport in the Thames Estuary, citing that the plan has 'substantial disadvantages that collectively outweigh its benefits'.

The proposal of 'Boris Island' was one among several being considered by the Airports Commission on the expansion of airport capacity in the UK.

The commission noted that the decision has been taken after careful consideration of a substantial body of evidence over the past few months.

"We need to focus on solutions, which are deliverable, affordable and set the right balance for the future of aviation in the UK."

Chaired by Howard Davies, the commission declared in a statement: "There are serious doubts about the delivery and operation of a very large hub airport in the estuary. The economic disruption would be huge and there are environmental hurdles, which it may prove impossible or very time-consuming to surmount.

"Even the least ambitious version of the scheme would cost £70bn to £90bn with much greater public expenditure involved than in other options, probably some £30bn to £60bn in total."

The commission was established in 2012 to look into the need for additional capacity, in order to maintain the UK's position as Europe's most important aviation hub.

In its December 2013 interim report, the commission identified the need for one new additional runway in London and the south-east and shortlisted three proposals to deliver this capacity.

"The need for additional capacity is urgent," added Davies.

"We need to focus on solutions, which are deliverable, affordable and set the right balance for the future of aviation in the UK."

The Telegraph newspaper reported that the commission will now continue further appraisal of the shortlisted proposals and will publish its recommendations for public consultation later in the year.

Following the UK Government's decision, Heathrow CEO John Holland-Kaye said: "We have always agreed with the mayor that UK needs a successful hub airport to compete in the global race for jobs and growth."