Shares in construction and property firm Henry Boot jumped over 8 per cent after it reported an "outstanding" year and said annual results will be materially ahead of existing forecasts.
The Sheffield-based firm said it has completed all the sales at the Chocolate Factory in York, two years before its deadline of mid-2019.
The factory, which was built in an Art Deco style with a distinctive clock tower, opened in 1926. The site developed and produced famous products such as Terry’s Chocolate Orange and Terry’s All Gold.
Henry Boot's CEO John Sutcliffe said: "We are delighted with how well the Chocolate Factory in York has performed.
"It's an iconic development that celebrates the city's rich history and customers have flocked to buy an apartment within the listed buildings.
"We have sold all of the apartments two years before our deadline which is a testament to the quality of the sympathetic development of this historical site."
The firm is now in discussions with York planners to bring forward the residential development of the former Clocktower buildings on the site.
The Clocktower development has detailed planning permission and Henry Boot is currently going through the agreement of a S106 negotiation with the planners in York.
The scheme is for 22 units, which is around 27,500 square feet of residential development space, and will include units within the Clocktower itself.
"The development will be in a similar style and quality to the existing main factory building and will further improve the look and amenity of whole site," said Mr Sutcliffe.
"The scheme will also see the iconic clock at the top of tower come back into use as part of the development."
Henry Boot has also agreed terms with the team who own and run the “Star in the City" contemporary restaurant in York and the "Star at Harome” 14th-century thatched inn near Helmsley, which has been awarded a Michelin star.
If planning is awarded, the Star team will run a restaurant, cafe and delicatessen, which will be housed in the former liquor store at the factory. Liquor was traditionally used in chocolate manufacturing.
The 27 acre former Terry’s Chocolate Factory site was acquired by Henry Boot in 2013 in partnership with David Wilson Homes.
The factory closed in 2005 with the loss of 300 jobs after parent company Kraft Foods decided to switch production abroad. Following closure the site fell into disrepair and in 2009, it was put on the at-risk register by English Heritage.
Today the site, which is adjacent to York Racecourse, has 236,806 square feet of iconic listed buildings plus cleared development land.
Henry Boot joined forces with P J Livesey to develop the main factory building into 165 luxury apartments. The remainder of the scheme will accommodate residential apartments within the converted listed buildings alongside a hotel and office accommodation.
The site won the “Best Design” award at the 2016 national Housebuilder Awards.
Henry Boot's shares closed up 26p to 333.5p following the update.
Mr Sutcliffe said: "2017 has proved to be an outstanding year where almost every deal we hoped to complete has done so. Furthermore, we concluded several deals in 2017, earlier than we had originally anticipated, including the sale of the final 30,500 sq ft industrial unit at Thorne, the sale of an 8,150 sq ft retail park in Monmouth and 80 residential units on land in Prestonpans.
"In addition, the delivery of several industrial units at Markham Vale has, once again, been quicker than forecast."
Within Hallam Land Management, the group's strategic land division, disposals on 14 schemes have been concluded this year including the final phases of sites at Biddenham for 233 residential units and Marston Moretaine for 183 residential units. In addition, it has already exchanged contracts on four schemes for 2018. Overall, the year to date sales represent 2,048 residential units, up from 1,609 units in 2016.
Within property development, the firm said the Aberdeen Exhibition Centre contract is going to plan and delivery of the project remains in line with expectations.
Mr Sutcliffe said: "We continue to backfill the opportunity pipeline and work on deals for 2018, thereby replacing the deals that have been executed earlier than expected, and there remains a possibility that some of these may conclude before the current financial year end.
"With this in mind, together with the wider UK economic backdrop, the group’s expectations for 2018 remain unchanged."