UK insurance broker Jardine Lloyd Thompson says profit up on weak pound

* Underlying pre-tax profit 100.1 mln stg vs 89.2 mln stg

* Interim cash dividend of 12.2 pence per share

* Total H1 revenue 689.9 mln stg vs 619.4 mln stg in 2016 (Adds detail, quotes)

By Dasha Afanasieva and Noor Zainab Hussain

LONDON, July 27 (Reuters) - Insurance broker Jardine Lloyd Thompson Group Plc (JLT) said on Thursday its first-half underlying pretax profit rose 12 percent to 100.1 million pounds ($131.44 million), helped by weakness in sterling since Britain's vote to leave the EU.

Revenue in the UK employee benefits business rose 8 percent to 149.1 million pounds, while trading profit was 2.9 percent higher at 17.9 million pounds, JLT said.

The unit saw tough trading conditions last year, hurt by a one-off structural shift away from commissions within the UK employee benefits market and reforms that allowed people over 55 years old more freedom over what to do with their pension funds.

"I'm pleased to say the unit has returned to health," Chief (Taiwan OTC: 3345.TWO - news) Executive Dominic Burke told Reuters.

Its U.S. speciality business more than doubled headline revenues to 35.2 million pounds for the period. The division remains on track to turn a profit for the first time, in 2019, it said.

JLT said in February that it saw an improving outlook for the U.S. speciality business, as oil exploration costs were falling and it expected President Donald Trump's policies to boost the building sector.

The firm said net investment in JLT USA was 13.4 million pounds in the period, reduced from 17.2 million pounds a year earlier.

Group pretax profit rose to 99.2 million pounds from 55.2 million pounds, driven by reduced exceptional items. Total (LSE: 524773.L - news) revenue rose 11 percent to 689.9 million pounds.

JLT said it would pay an interim cash dividend of 12.2 pence per share, up from 11.6 pence per share a year earlier.

($1 = 0.7616 pounds) (Reporting by Dasha Afanasieva in London and Noor Zainab Hussain in Bengaluru; Editing by Rachel Armstrong and Edmund Blair)