UK's FTSE slips off record highs as weak China data hit miners

* FTSE 100 falls 0.5 pct, falling off Friday's record highs

* Miners hurt by weak Chinese trade data

* YouGov (LSE: YOU.L - news) poll gives Labour lead before May 7 election

* Aviva (Other OTC: AIVAF - news) boosted by upbeat broker notes (Adds detail, quotes)

By Alistair Smout and Sudip Kar-Gupta

LONDON, April 13 (Reuters) - Britain's top equity index slipped from record highs on Monday as surprisingly weak data from China weighed on mining stocks, with investors also growing cautious before May's general election in the U.K.

The blue-chip FTSE 100 index, which touched a record high of 7,095.36 points on Friday, retreated 29.29 points, or 0.4 percent, to 7,060.48 points by 1313 GMT. The FTSE remains up around 8 percent since the start of 2015.

Miners such as BHP Billiton (NYSE: BBL - news) , Anglo American (LSE: AAL.L - news) and Rio Tinto (Xetra: 855018 - news) were among the worst performers.

China's exports, which had been expected to rise 12 percent, dropped 15 percent in March. Its imports saw the biggest decline since the global financial crisis in 2009, heightening concern that Chinese economic growth is slowing.

The Chinese stock market shrugged off the data Shares (Berlin: DI6.BE - news) rose on expectations the poor trade figures would put pressure on Beijing to add new economic stimulus.

Citigroup (NYSE: C - news) , however, forecast that slowing demand from China would hurt iron ore prices, which in turn would put pressure on UK mining stocks.

"You've had the downgrade from Citi on the miners, which along with the data from China hasn't helped that sector," said Manoj Ladwa, head of trading at TJM Partners. "After making all- time highs, it's natural to have a small pullback."

Caution was also growing before Britain's election on May 7. The opposition Labour party has taken a 3 percentage-point lead over Prime Minister David Cameron's Conservatives, according to a YouGov poll released late on Sunday. However, a TNS poll said the Scottish National Party extended its lead over Labour in Scotland, making a Labour majority less likely.

A Labour-led government would see more regulatory scrutiny of utilities and banks, while the Conservatives have promised a referendum on Britain's EU membership.

"We are using this as an opportunity to decrease our UK holdings," said Atif Latif, director of trading at Guardian Stockbrokers. "(We) see severe downside risk into the Election for the UK market ... with the market being again at a new high, we see greater downside risk at this juncture and look to lower entry levels for UK equity prices."

A Bank of America Merrill Lynch downgrade pushed housebuilder Barratt Development 2.6 percent lower, traders said, falling from its highest level since September 2007.

Insurer Aviva, on the other hand, rose 2.1 percent after both Morgan Stanley (Xetra: 885836 - news) and JP Morgan reinstated their coverage of the stock with "overweight" ratings.