PLANS for a controversial scheme to improve a notorious Hampshire bottleneck and service a new housing development have taken a blow after construction costs more than doubled.

Costs to upgrade junction 10 of the M27 into a full-flow junction have risen from £30m to more than £60m following an unsuspected surge in infrastructure costs.

Now, following a meeting of Hampshire County Council’s cabinet last Friday, councillors agreed to bid for a share of up to £250m from central government’s Housing Infrastructure Fund ito cover the increase.

The scheme at junction 10 will be delivered by Hampshire County Council, Highways England in partnership with Buckland, developers of the new 3,000-home garden village at Welborne.

Currently traffic can only leave the motorway on the westbound carriageway and join it on the eastbound carriageway however the plans will see the construction of a new eastbound off and a new westbound on sliproads.

Councillor Sean Woodward, the leader of Fareham Borough Council, said: “We will not lay down a brick in Welborne until all of the required infrastructure is identified, where it’s going to go and how it’s going to be funded.

“I welcome any additional funding that HCC can obtain for the project.”

Mark Thistlethwayte, principal of Buckland Development, said: “We are continuing discussions with Fareham Borough Council, Hampshire County Council and Highways England to ensure that the Junction 10 improvement works can be brought forward in a timely manner and are integrated with Highways England’s M27 smart motorway proposals.”

However, opposition Councillor Shaun Cunningham, who represents Portchester on Fareham Borough Council said: “I have concerns about the affordable homes element could be taken out of Welborne because the developer could incur unexpected costs.”

The project is expected to start by 2020 subject to planning consent for Welborne.