UPDATE 2-Trade hopes lift FTSE 100, SIG drags down mid-caps

* FTSE 100 up 0.6%, FTSE 250 dips 0.3%

* Hopes for U.S.-China deal help blue-chips

* Mid-cap SIG plummets after profit warning (Adds company news items, updates share moves)

By Muvija M and Shashwat Awasthi

Oct 7 (Reuters) - Oil majors led a rebound in London's FTSE 100 on Monday as investors hoped for a U.S.-China trade deal, while a sell-off in the construction sector after a profit warning from SIG and scepticism over the chances of a Brexit deal knocked midcaps.

The main index, which had suffered its worst week in nearly a year in the face of global trade tensions and the risk of a recession, shrugged off early losses to close 0.6% higher.

Shell and BP climbed about 1% on a surge in crude prices.

Broader gains were fuelled by hopes of an end to the stand-off between the world's largest economies, with U.S. President Donald Trump saying his administration had a "very good chance" of making a trade deal with China.

Washington is set to host Chinese officials later in the week to further trade talks.

The FTSE 250 missed out, however, ending 0.3% lower. Losses were led by a 16% plunge in building materials supplier SIG after it said weaker construction activity in the UK would hit annual profit in its core units.

SIG's peers Travis Perkins and Howden Joinery lost 2.1% and 3.1%, respectively, making industrials the biggest sector drag on the midcap index.

A dip in the pound, due to fears that sizeable differences remain between Britain and the European Union over a potential Brexit deal, also weighed on domestic stocks.

Companies which earn a chunk of their earnings in the greenback, including spirits company Diageo and GlaxoSmithKline, edged higher as a fall in sterling means the value of their earnings go up.

Despite yield curves remaining inverted on UK bonds for the second straight day and the FTSE 100 trading below its 200-day moving average - a key technical support -, market participants pinned their hopes on this week's Sino-U.S. trade talks.

"If the world economy does start to slow down, that's a much bigger impetus for China and the U.S. to get a trade deal done," Randeep Somel from M&G Investments' global equities team said.

British Airways owner IAG added 3.1% after saying it carried more passengers last month compared to the year-earlier period.

Troubled lender Metro Bank, which was recently demoted from the midcap index, jumped as much as 10% after a report that its founder Vernon Hill was working to take the company private. The stock, which has plummeted nearly 90% this year, closed up 2.2%. (Reporting by Shashwat Awasthi, Muvija M and Indranil Sarkar in Bengaluru; Editing by Bernard Orr and Mark Potter)