(Adds more comment, updates prices)
* Lawmaker's murder seen changing sentiment on Brexit
* Traders talk of Britain's EU referendum being delayed
* Sterling and euro gain, yen also holds strong
* One-week volatility on euro, pound hit multi-year highs
By Patrick Graham
LONDON, June 17 (Reuters) - Sterling rose half a percent in early London trading on Friday and the euro added to gains in the past 24 hours on expectations that the killing of a pro-EU British lawmaker may alter the balance of opinion in Britain's referendum on EU membership.
Speculation was rife among traders after the murder of Jo Cox on Thursday that Prime Minister David Cameron might push back the vote due to take place on June 23.
There has been no such signal from Downing Street, but either way some traders think the murder will turn the tide of public opinion after a series of polls showed the "Leave" campaign moving ahead.
Concerns Britain would send a shockwave through global financial markets and European politics by voting to leave the 28-country bloc have prompted a flood of money into traditional safe havens such as the yen and the Swiss franc.
"For now the bounce is only really visible in sterling," BNP Paribas (PA:BNPP) strategist Michael Sneyd said.
"The biggest move this week has been the shift in Fed expectations, which we have seen in surge in the yen against the dollar. What's interesting is the euro has not reacted, which suggests there has been an increase in risk on the euro itself."
By 1120 GMT, sterling was up 0.6 percent at $1.4276, almost 3 cents above Thursday's lows. It also gained 0.2 percent to 78.85 pence per euro. The single currency firmed a third of a percent to $1.1257 EUR= from a two-week low of $1.1131.
The cost of hedging against volatility in sterling and the euro over the next week hit multi-year highs, however, reflecting the risk of a sharp move either way for both next Thursday.
The yen also remained within sight of almost two-year highs of 103.55 yen hit against the dollar on Thursday.
"Past the date of the referendum, asset prices are likely to move sharply, regardless of the outcome of the referendum," Goldman Sachs (NYSE:GS) strategists said in a note on Friday.
The U.S. bank said the Swiss franc would be the biggest gainer against both the euro and sterling in the event of a vote to leave. The franc gained 0.4 percent against the dollar compared to the market close in New York. CHF= It hit its highest against the euro this year on Thursday. EURCHF=
Analysts from Credit Agricole (PA:CAGR) closed some risk-averse bets in response to Thursday's events and a minimal recovery in investors' appetite for risk overnight, but they remained cautious.
"We believe it is premature to conclude that the risk of Brexit will abate from here," they said in a note.
"Polls in coming days should offer an indication of whether voter sentiment has shifted. We therefore remain fairly cautious on the outlook for sterling, the European and the commodity G10 currencies."
The dollar last stood at 104.34 yen JPY= . (Editing by Janet Lawrence)