* Miners rally on China infrastructure spending plans
* UK regulatory investigation hits insurance stocks
* FTSE 100 up 0.5 pct in mid-session trading
By Tricia Wright
LONDON, March 28 Britain's top equity index rose on Friday, buoyed by gains in mining stocks which outweighed another slump in the insurance sector, which was hit by signs of further regulatory pressure.
The blue-chip FTSE 100 index, which rose 14.4 percent in 2013 and came close to hitting its highest level since early 2000 in January this year, was up by 0.5 percent - or 33.67 points - at 6,621.99 points.
The FTSE 350 Mining Index has been a perennial underperformer over the last year, falling 16 percent in 2013 due to persistent concerns about an economic slowdown in China - the world's biggest metals consumer.
But the sector recovered on Friday after Chinese Premier Li Keqiang said Beijing was ready to support its cooling economy and push ahead with infrastructure investment.
China's economic health tends to affect the FTSE 100 since miners account for almost 9 percent of the index, according to data from index compiler FTSE.
"The current belief that China is not going to let the economy fall too much should be supportive for the FTSE, and especially for the miners which on a relative basis have become attractive to some investors," said Lex van Dam, hedge fund manager at Hampstead Capital.
A fall in major insurance stocks prevented the FTSE from making bigger gains.
Insurers, already hit this month by a government shake-up of the UK pensions system, slumped again on news Britain's financial watchdog was planning an investigation into whether people sold pensions and savings plans in the past were treated fairly compared to new clients.
"Should investors be allowed to exit policies and look for a better deal, the sector may be punished with large out-flows of money from some zombie funds," said Mike van Dulken, head of research at Accendo Markets.
The FTSE is down by around 2 percent since the start of 2014.
Strand Capital managing director Kyri Kangellaris expected the FTSE to be stuck in a range from 6,500-6,850 points, as long as the index failed to break above its January high of 6,867 points and last year's peak of around 6,876 points.
"We're looking range bound for the near-term," he said. (Additional reporting by Tricia Wright and Atul Prakash; Editing by Andrew Heavens)