The development at the 137-room Aubrey Park hotel in Redbourn is projected to provide a 30 per cent increase in local employment and boost trade with suppliers by £500,000.
It follows a recent £3m refurbishment programme at the hotel which saw the site granted a 4-star grading by the AA.
Work will begin this year with the venue set to open in Spring 2016.
“We are delighted to have been granted planning permission for our new venue, which will complete our full range of facilities in order to sustain the long term success of the hotel ’, said David Timmis, managing director of Aubrey Park Hotel.
The new development will cater for up to 250 guests and feature energy efficient lighting, a top of the range sound system and interactive white boards
As well as preserving the Grade II listed original building, Aubrey Park will open up the once hidden Iron Age Fort to the public at no cost to the local community.
‘We are committed to improving the environment we work within and have agreed a five year plan to improve 'The Aubreys' for guests and local residents alike,” said Timmis.