LONDON (Reuters) - A key market measure of the euro zone's long term inflation expectations extended its falls to a new record low on Monday, as concerns about the outlook for growth and inflation rise in the wake of last week's UK Brexit vote.

The five-year, five-year breakeven forward -- the European Central Bank's favored measure of market inflation expectations -- fell to 1.276 percent <EUIL5YF5Y=R>, a record low.

It is has tumbled from above 1.40 percent just before Thursday's UK referendum on European Union membership and is well below the ECB's inflation target of near 2 percent.

"The record low on the five-year, five-year forward highlights not just the flight to quality post the Brexit vote but also the negative impact on the economic outlook from Brexit," said Richard McGuire, head of rates strategy at Rabobank. "This raises the chance of the ECB providing more monetary stimulus soon."

(Reporting by Dhara Ranasinghe; editing by Nigel Stephenson)