UK business software company Sage hit by data breach

(Adds further details on nature of the security breach)

LONDON, Aug 14 (Reuters) - Sage Group (LSE: SGE.L - news) , a provider of accounting, payroll and payments software for businesses, said an internal login had been used to gain unauthorised access to the data of some of its British customers.

The personal details of the employees of about 280 British companies were potentially exposed in the breach, a company source said. It was working to ascertain whether any data had been stolen, the source added.

"We are investigating unauthorised access to customer information using an internal login," the company said in a statement.

"We cannot comment further whilst we work with the authorities to investigate but our customers remain our first priority and we are speaking directly with those affected," it added.

Sage, one of Britain's largest technology companies, says it has more than 6 million small and medium-sized businesses using its software worldwide.

It said last month it was confident its revenue would increase by at least 6 percent in the current year ending next month, continuing a pace set in the six months to end-March, when revenue rose 6.2 percent to 747 million pounds ($966 million).

In the same period its operating profit rose by 1.9 percent on a like-for-like basis to 189 million pounds. ($1 = 0.7736 pounds) (Reporting by Paul Sandle; Editing by Greg Mahlich)