Work to widen the A303 and A358 will not begin until 2020 at the earliest.

Highways England (HE) says it needs to review options, consult stakeholders and secure planning consent.

Work to improve the A358 is not expected to begin until 2020, Highways England has said.

The dual carriageway plan progress report was given to Somerset County Council this week. This follows election promises by the transport ministry the work would start soon. The project involves upgrading the A303/A358/A30 corridor from the M3 to the M5 in Taunton, Somerset.

Cabinet member David Fothergill, who is responsible for highways, called the timescale "really disappointing".

An HE spokesman said: "Further consultation will also take place during the development of the preferred solution as part of the statutory requirements of the planning process to obtain development consent."

Due to the timescales, the county council said its plans to improve junction 25 of the M5 will continue.

Mr Fothergill told the BBC: "Highways England need to incorporate whatever we've done [on junction 25] into their planning for the A358 and they've indicated that they will," Mr Fothergill continued.

"We are at such an advanced stage now on junction 25, to stop it for us now will cause a real disappointment and causes more hassle that people really don't want."