* Sees comparatively subdued market conditions in Q4
* Q3 revenue rise 3 pct to 420 mln stg
* Finance chief Andrew Baddeley to leave in December
* Shares slump 9 percent (Adds details, analyst comments, share movement, share chart)
Nov 3 (Reuters) - TP ICAP, the world's largest interdealer broker, said on Friday its finance director was leaving and flagged a challenging outlook for the final quarter of 2017.
ICAP gave no reason for the departure of Andrew Baddeley, who is stepping down from its board with immediate effect and leaving TP ICAP in December, and blamed a relative lack of volatility for its downbeat forecast.
Shares in TP ICAP fell 6.3 percent to 502 pence at 0815 GMT, after falling more than 9 percent, making it London's worst Midcap performer.
"The shock news is that Baddeley is stepping down ... This is a real surprise and a disappointment and unlikely to be received well initially," Liberum analyst Justin Bates, who rates TP ICAP as "buy", said.
Baddeley had overseen the integration when Tullett Prebon bought ICAP's hybrid voice broking unit late last year and started as TP ICAP's finance chief in May last year.
A source with knowledge of the matter said Baddeley was moving on to pursue other professional opportunities.
TP ICAP, which brings together buyers and sellers in financial, energy and commodities markets, said revenue for the three months to the end of September rose 3 percent year on year to 420 million pounds ($548 million).
The final quarter of last year was marked by increased market volatility after unexpected outcomes in global politics, such as Donald Trump's victory in the U.S. presidential election and speculation over higher U.S. interest rates.
"Looking ahead we expect comparatively subdued market conditions for the fourth quarter of 2017, although we are well-placed to benefit from any interest rate rises in the U.S. and Europe," Chief Executive John Phizackerley said.
The Bank of England raised interest rates for the first time in more than 10 years on Thursday.
Global Broking revenue for the third quarter was in line with a year earlier, TP ICAP said, adding that energy and commodities revenue was down 1 percent, with market conditions remaining particularly challenging in power and commodities. ($1 = 0.7659 pounds)
(Reporting by Noor Zainab Hussain in Bengaluru; Editing by David Goodman and Alexander Smith)