Profits at Thorntons tumbled over the past six months as the confectioner resorted to selling more chocolate on promotion.

Pre-tax profits in the 28 weeks to 7 January slumped to £618,000, down from £8.3m in the previous year.

Thorntons said gross margins had dropped four percentage points to 42.5% as a result of selling more promotional lines and shifting the sales emphasis from its own stores to other retailers.

Also as a consequence of own store sales falling short of expectations over the period, Thorntons incurred gross impairment and onerous lease charges of £2.4m.

Thorntons CEO Jonathan Hart said the results reflected the need for the company to stick to its strategy of building sales through other retailers while reducing the size of its own retail estate, which he said would still remain “an important shop window for the brand”.

Thorntons closed 20 stores over the most recent trading period and has earmarked at least 120 stores for closure over the next three years, leaving an estate of between 180 and 200 stores.

“We are pursuing our chosen strategy and have made good progress in implementing it while weathering a difficult market,” said Hart. “These results and the economic climate only reaffirm the need for change.”