* FTSE closes up 0.4 pct at 6,615.58 points

* UK regulatory investigation hits insurance stocks

* China infrastructure spending plans boost miners

* Investec (LSE: INVP.L – news) upgrade lifts Smith & Nephew (LSE: SN.L – news)

By Sudip Kar-Gupta

LONDON, March 28 (Reuters) – Britain’s top equity index rose on Friday, buoyed by gains in mining stocks that outweighed another slump in the insurance sector, which was hit by signs of further regulatory pressure.

The blue-chip FTSE 100 index closed up by 0.4 percent, or 27.26 points, at 6,615.58 points.

The index, which rose 14.4 percent in 2013 and came close to hitting its highest level since early 2000 in January this year, also progressed by 0.9 percent over the week.

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 mining index rallied by 1 percent 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.

Toby Campbell-Gray, head of trading at Tavira Securities, said mining stocks were an attractive choice for “value” investors – investors who seek out stocks that have fallen to a level at which they are now seen as a good bargain.

“The value players will move in on a day like today and pick up stocks like the miners,” said Campbell-Gray.

INSURANCE HIT

Healthcare group Smith & Nephew also rose 2.4 percent, making it the top performer on the FTSE in percentage terms, after brokerage Investec raised its rating on the stock to “buy” from “add”.

However, a drop in major insurance stocks prevented the FTSE from making bigger gains.

Insurers, already hit this month by a government shake-up of the pensions system, slumped again on news that 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.

Insurance group Resolution slumped 7.1 percent while rival Legal & General (LSE: LGEN.L – news) declined by 3.5 percent.

“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. Tavira Securities’ Campbell-Gray expected the FTSE to make little headway until the fourth quarter of 2014, which was when he felt the market could rally to hit a record of 7,000 points.

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,” said Kangellaris. (Additional reporting by Tricia Wright and Atul Prakash; Editing by Alison Williams)