* FTSE 100 down 0.3 pct
* WPP, Berendsen fall after results
* Precious metals miners under pressure
* Shawbrook spikes after private equity acquisition offer (Updates at close)
By Kit Rees and Helen Reid
LONDON, March 3 (Reuters) - Britain's top share index retreated on Friday, weighed down by a raft of disappointing earnings updates as well as weakness in the mining sector.
The blue chip FTSE 100 index was down 0.1 percent at 7,374.26 points by 1630 GMT, having hit a record high in the previous session. It closed the week higher, however, posting its best weekly gains since December, up 1.8 percent.
Weak earnings dampened the mood on the day.
WPP, the world's largest advertising group, saw its shares drop 8 percent after the firm expressed concerns about the outlook for 2017, cutting its sales forecasts on the back of a bleak economic environment.
"This suggests a worrying continuation of what (WPP) terms a 'tepid' macro environment, clients 'grinding it out in a highly competitive game' and a cooling of positive tail winds," Mike van Dulken, head of research at Accendo Markets, said.
"Not really what investors want to hear when shares are just shy of all-time highs."
Britain's mid caps also did not escape unscathed after shares in commercial laundry firm Berendsen tanked nearly 17 percent, before recovering to close down 11.4 percent.
Berendsen said that it expected performance in the first half of 2017 to be impacted by legacy operations in the UK.
Miners were also putting pressure on UK shares, as precious metals miners Fresnillo among the blue chips, and mid-caps Hochschild and Centamin, all fell between 2.9 and 6.6 percent, tracking the price of gold lower.
Gold eased ahead of a speech by U.S. Federal Reserve Chair Janet Yellen, with the possibility of an interest rate hike later in March helping the dollar make gains this week.
"The chances of a rate hike at the next Fed meeting have increased from 30 percent just a couple of weeks back to 90 percent, so there's a lot more realisation that the U.S. could be raising rates that bit sooner," Dafydd Davies, partner at Charles Hanover Investments, said.
"Of course (on) the FTSE 100 you've got a fair few mining stocks... with the strong dollar that could actually affect demand for the products they're pulling out of the ground."
Acacia Mining was the top mid-cap faller, down 13.5 percent after the Tanzanian government announced it was banning gold/copper concentrate exports from the country.
The miner's three gold mines are in Tanzania, and gold/copper concentrate accounts for approximately 30 percent of group revenues, Acacia said in a statement after the move, adding it was seeking clarification from the Tanzanian ministry of Energy and minerals.
Shares in challenger bank Shawbrook spiked, closing up 18.2 percent, its biggest daily gain in eight months, after it said private equity firms Pollen Street Capital and BC Partners had offered to buy the lender in a deal worth 825 million pounds ($1.01 billion). (Reporting by Kit Rees; Editing by Toby Chopra and Ken Ferris)