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* Broker TP ICAP slips as first-half profit falls

* UK PM raises taxes to tackle health crisis

* 888 in talks to buy William Hill's non-U.S. assets; shares down

* FTSE 100 down 0.5%, FTSE 250 off 0.6%

Sept 7 (Reuters) - London's FTSE 100 index ended lower on Tuesday, weighed down by healthcare stocks and brokerages, while DS Smith jumped to the top of the index after an upbeat trading update.

The blue-chip index fell 0.5% and marked its worst session in nearly three weeks, as healthcare weighed with drugmakers AstraZeneca and GlaxoSmithKline among top drags.

Investment banking and brokerage services providers shed 1% after TP ICAP Group Plc reported a lower half-year profit.. Shares of the world's largest inter-dealer broker slipped 10.7%.

DS Smith jumped 2.8% to the top of the index as J.P. Morgan raised its price target on the cardboard maker's stock after it said trading continued to progress well in line with the trends.

European stocks edged down as investors awaited the European Central Bank's policy meeting on Thursday for clues on how the crisis-fighting measures would be dismantled.

"After a weak US jobs report last Friday prompted speculation the Federal Reserve would hold off on tapering support for the economy, attention will switch to the European Central Bank this week as it unveils its latest decision on monetary policy on Thursday," said Russ Mould, investment director at AJ Bell.

Meanwhile, British Prime Minister Boris Johnson set out plans to raise taxes on workers, employers and some investors to try to fix a health and social care funding crisis sending pound down.

The domestically focused mid-cap FTSE 250 index was down 0.6% dragged by industrial stocks.

Among individual stocks, 888 fell 1.8% after the British gambling group said it was in advanced talks with Caesars Entertainment for a possible acquisition of the international operations of the U.S. company's William Hill business.

Meggitt Plc fell 12.1% to the bottom of mid-cap index after aerospace parts maker TransDigm bowed out of an $8.7 billion takeover battle with fellow U.S. bidder Parker-Hannifin for the British engineering firm. (Reporting by Devik Jain and Amal S in Bengaluru; Editing by Saumyadeb Chakrabarty and Uttaresh.V, Editing by William Maclean)