(Reuters) - ICAP Plc, the world's largest inter-dealer broker, has unveiled indexes that track British job numbers in the latest example of brokerages aiming to offset weak trading with new services.

ICAP said on Tuesday it had launched its UK Labour Market Indices, a series of data sets offering investors, traders and researchers guidance on British employment, vacancies and salaries.

The broker said the new service will be valuable for clients because it will provide them with data on British employment levels for each calendar month days before the public figures are made available.

"These indices ... are based on a unique source of employment information, covering more than 60 per cent of all job listings in the UK, providing data earlier and with greater granularity than information currently available to financial market participants," said Kevin Taylor, Global Head of ICAP Information Services.

ICAP, and rivals such as Tullett Prebon and BGC Partners, draw ther majority of their revenue from matching buyers and sellers of bonds, currency and swaps.

But these firms have struggled to sustain income in recent years as the financial crisis has forced investors to pull back from the markets.

ICAP revenue for the year to the end of March 2012 was down 3 percent to 1.68 billion pounds ($2.64 billion), with Chief Executive Michael Spencer blaming a difficult economic environment.

The brokers have responded by looking to develop more stable revenue streams, including information services, a move that takes them away from their traditional broking businesses.

ICAP has pledged to continue investing where there are opportunities and last month bought a loss-making stock market from PLUS Markets Group, a London-based exchange group.

The broker has bought the stock exchange to help it expand into listed futures trading, a relatively new sector for ICAP that is likely to be opened up to new entrants by European regulatory reforms.