The UK’s biggest nightclub operator today offered no sign that Britons are getting back in the party mood as surging unemployment curbs spending among young clubbers.

Luminar, which owns Oceana and Liquid clubs, said underlying pre-tax profits in the six months to August 27 plunged to £4.9m from £8.4m a year earlier as like-for-like sales dived 4.5%.

However, it warned that trading in its new financial year has worsened further, with same-outlet sales plummeting 14% in the seven weeks to October 15 as admissions sank 16.6%.

The grim update comes a month after Luminar, which operates 88 sites, issued a profit warning, blaming a recent jump in unemployment among its core 18-24 year-old customers for a slump in trading.

The company had previously weathered the recession relatively well, with young mortgage-free consumers among those still spending during the early stages of the downturn.

But rising levels of young joblessness are now hitting Luminar hard.

Luminar said: “Some 18% of 18-24 year-olds are now unemployed, and many more are students, or on low incomes.

“Whilst our customers undoubtedly value the high energy experience of a Luminar nightclub, they are more economically constrained in their leisure activities, as our lower admission numbers demonstrate.”

Total customer admissions during the half-year period fell to 7.1m from 7.6m a year earlier although average spending per customer edged up 0.7% to £12.50 despite falling drink prices.

Overall sales fell to £88.7m from £94.3m.

Alongside the tough conditions, the company was also hit with a £9.9m write-down on its 49% investment in Jumpin’ Jacks bar operator 3D Entertainment.

Luminar has launched an action plan to deal with the downturn, including a crackdown on costs.

Stephen Thomas, chief executive, said: “Whilst our market is currently very tough we continue to have a clear operational focus.

“This together with very tight cost control and significant financial strength will ensure that Luminar maintains its market leading position and prospers when our marketplace recovers.”

The firm said it has prepared well for the crucial Christmas trading period but warned of the negative impact of Christmas Day falling on a Friday - typically one of its busiest days.

Simon French, analyst at broker Panmure Gordon, described current trading as “horrendous” and said the update raised concerns over the company’s ability stay within its debt covenants.

Panmure is forecasting full-year pre-tax profits of £10.3m, down from £20.3m a year earlier.

Shares in the company, which have plunged 40% in the past month, fell a further 1% today.