UPDATE 1-Spirent trading slightly ahead of expectations

* The year set to be line with expectations

LONDON, May 7 (Reuters) - British telecoms testing firm Spirent Communications (SPT.L) said trading since the start of the year was slightly ahead of expectations, with operating profit for the first quarter up 20 percent.

The group also said it expected its performance for the rest of the year to continue to be in line with its forecasts.

"Market conditions were generally as expected," Chief Executive Bill Burns said in a statement.

"A favourable U.S. dollar sterling exchange rate, improved margins resulting from a favourable mix of new products, and continuing expense control offset the impact of lower revenues in U.S. dollar terms on operating profit."

"We are pleased at the level of profits reported in our seasonally weakest quarter. Our new product introductions for wireless and broadband test solutions will position Spirent well to serve the needs of our markets for the rest of this year and beyond."

Cost reductions in the first quarter of 2009 will result in 8.5 million pounds of annualised savings, it said.

(Reporting by Kate Holton)