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FTSE 100 down 1%, FTSE 250 off 0.8%

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Energy stocks lead declines as oil prices slip

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i3 Energy ( ITEEF ) rises on $226 mln takeover offer

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U.S. Fed Chair Powell's speech at Jackson Hole awaited

(Updated at 1540 GMT)

By Khushi Singh and Purvi Agarwal

Aug 20 (Reuters) - The UK's FTSE 100 ended 1% lower on

Tuesday, as a third straight day of falling crude prices weighed

on energy stocks, and BT dropped to the bottom of FTSE 100 after

rival CityFibre struck a deal with Sky.

The blue-chip FTSE 100 index had its biggest one-day

decline since Aug. 5, while the mid-cap FTSE 250 lost

0.8%.

Energy shares slipped 2.8%, leading sectoral

declines, as oil prices responded to expectations of weak

Chinese demand and efforts to agree a ceasefire deal in Gaza,

potentially easing supply concerns.

Sector majors Shell and BP fell nearly 3%,

each.

Shares of telecom giant BT Group tumbled 6.4% after

internet provider rival CityFibre signed a deal with BT's

existing partner Sky to launch Sky's broadband services on the

CityFibre network.

Gains were led by precious metal miners that

added 0.8% as gold prices continued a record run, driven by a

weaker dollar and growing investor confidence that the Federal

Reserve will cut interest rates in September.

Among individual stocks, shares of i3 Energy ( ITEEF ) jumped

as much as 28% after Canada's Gran Tierra Energy ( GTE )

offered to buy the British oil and gas producer in a deal valued

at 174.1 million pounds ($226.23 million).

Antofagasta ( ANFGF ) gained marginally after the Chilean

miner posted a rise of 5% in half-year profit.

Investors are focused on Fed Chair Jerome Powell's speech at

the annual Jackson Hole economic symposium in Wyoming later this

week.

Purchasing managers index (PMI) numbers in the UK and U.S.,

alongside minutes of the Fed's last meeting are also on the

market's radar in a relatively data-light week.