(Adds sterling jump on inflation, more comment, updates prices)
* Centrist Macron seen as victor in marathon TV debate
* Euro up 0.6 percent to six-week high
* Dollar index dips below 100, first time since early Feb
* Sterling surges after higher inflation print
* Graphic: World FX rates in 2017 http://tmsnrt.rs/2egbfVh
By Patrick Graham
LONDON, March 21 (Reuters) - The euro rose above $1.08 for the first time in six weeks on Tuesday as centrist Emmanuel Macron's performance in a TV debate fuelled expectations he would win the French presidency ahead of far-right rival Marine Le Pen in May.
After four days of trading focused chiefly on expectations for U.S. interest rates and the Trump administration's attitude to trade and a stronger dollar, the euro's gains also sent the dollar index to a six-week low.
A cautious line from Federal Reserve speakers since it raised rates last week has added to signs the Trump team will have to take its time in delivering a promised fiscal boost to the economy.
There has also been an easing of some of the perceived political risks to the euro from populists such as Le Pen, who wants to take France out of the single currency, and speculation the European Central Bank will rein in its ultra-loose monetary policy later this year.
A snap opinion poll after Monday's debate showed Macron, a former economy minister who has never run for public office before, was seen as the most convincing among the top five contenders for the French presidency.
"The euro has been helped by Macron's performance definitely," said Stephen Gallo, head of European FX strategy at Bank of Montreal in London.
"I still want to buy dollars but not here. I think there will be a push higher in euro dollar in the very short run, before we would look for levels to be selling."
The euro rose 0.6 percent to $1.0808 by 1134 GMT. That pushed the index used to measure the dollar's broader strength below 100 for the first time since early February.
The euro was also 0.7 percent higher against the yen.
Sterling, a target for investors this year due to nerves over the UK economy's performance in the face of its planned departure from the European Union, jumped almost 1 percent after higher than expected inflation data.
Signs price rises are beginning to outstrip wage gains bodes ill for household budgets and consumer spending but also fuel expectations that the Bank of England may be forced to raise interest rates to support the pound.
The Bank's meeting last week shocked markets by showing one outgoing policymaker already switching to vote for higher rates and others on the verge of following if inflation and inflation expectations continue to rise.
"With the BoE now indicating it could raise rates much sooner than markets were expecting ... future downside for the pound now looks far more limited, especially as it's the pound's depreciation that has generated much of the inflationary pressures," said Oanda market analyst Craig Erlam.
Sterling rose almost 1 percent to a three-week high of $1.2474 in morning trade in London. It inched up 0.2 percent to 86.73 pence per euro.
For Reuters Live Markets blog on European and UK stock markets see reuters://realtime/verb=Open/url=http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageId=livemarkets
(Writing by Patrick Graham; Editing by Mark Trevelyan/Keith Weir)