* Graphic: World FX rates in 2019 http://tmsnrt.rs/2egbfVh
* Graphic: Trade-weighted sterling since Brexit vote http://tmsnrt.rs/2hwV9Hv
By Elizabeth Howcroft
LONDON, November 29(Reuters) - The pound slipped back below $1.29 on Friday while implied volatility gauges with a two-week maturity, straddling the UK's general election date, jumped.
Implied volatility gauges for both cable and euro-sterling maturing on Dec. 13 - the day the Dec. 12 election results will be known - were at their highest in five weeks as investors hedged their bets for election uncertainty.
Sterling mostly held on to gains against both the euro and the U.S. dollar after a major poll by YouGov released on Wednesday predicted that Prime Minister Boris Johnson's governing Conservative Party would win its biggest majority in parliament since 1987.
Despite some gains from the poll, sterling is heading for its quietest month since August, down around 0.2% so far in November - a small monthly move compared to October, where it rallied 5.2%.
Versus the dollar, the pound slipped below $1.29 and against the euro it was flat at 85.350 pence.
"I think this week's big news was that YouGov opinion poll a couple of days ago - the market's waiting for the next headline," said Jane Foley, senior FX strategist at Rabobank.
Foley noted that Johnson appears to be avoiding scrutiny by turning down broadcast interviews in an attempt to hold on to his lead in the polls.
Boris Johnson did not appear in a televised debate on British broadcaster Channel 4 on Thursday and has declined to take part in a half-hour sit-down with BBC interviewer Andrew Neil, who gave tough scrutiny to Labour leader Jeremy Corbyn on Tuesday.
"It appears that his advisors are trying to prevent him from making any major gaffs," Foley said.
"It does appear that they don't 100% trust what he will say when he opens his mouth and therefore the best thing to do is not give him the opportunity," she said.
Foley said that if this is the case then there will be little news from the Conservative campaign other than reiteration of their pledge to get Brexit done, and news about spending, which would leave sterling in a "holding position" for the next two weeks.
The market was unchanged by comments from Johnson on Friday morning that he would guarantee the UK's departure from the EU on Jan. 31 and would not extend the transition period.
(Reporting by Elizabeth Howcroft; Editing by Andrew Heavens)