UK midcaps broke a three-day losing streak on Thursday but still lagged the FTSE 100, with investors clearing the decks as Britons voted in a general election that could decide the fate of Brexit.

The FTSE 100 added 0.6% with all sectors up by 0900 GMT. Broader sentiment was supported by the U.S. Federal Reserve signalling that interest rates would likely remain accommodative. 

The more domestically-inclined FTSE 250 only managed a 0.1% gain, with traders opting for a wait-and-watch approach as voting got under way.

"The moves are relatively modest. At this stage, people are waiting for the exit polls and the election results in the due course... We are seeing a FTSE 100 out-performance but in the wider scheme of things, it is modest," Raymond James analyst Chris Bailey said.

Polls in the run-up to the election had indicated that Boris Johnson's Conservative Party would win a majority, but recent estimates have shown that its lead over the opposition Labour Party narrow, stoking worries of a hung parliament.

Still, more UK-focussed stocks such as housebuilders recorded mild gains, and Bailey said the past month's signs of a clear Conservative majority were continuing to prop up sentiment.

Travel-related stocks such as tour operator TUI and British Airways owner IAG jumped 2%.

"If you do get an election result which is clear...then you will once again see American money start to look at the UK market," Bailey said.

Reining in gains among midcaps was a 12% fall in infrastructure firm John Laing. Its share were on course for its worst day ever, after the company said it expects annual net asset value to miss market estimates. Balfour Beatty  rose 3.3% after forecasting annual profit ahead of its estimates and electricals retailer Dixons Carphone added 5% as it maintained its full-year outlook. 

While investors would have preferred Brexit never to happen at all, moves in both sterling and stock prices have shown they are concerned that the result of the election may further drag out the process.

(Reporting by Muvija M and Shashwat Awasthi in Bengaluru; Editing by Arun Koyyur) ((muvija.m@tr.com; within UK +44 20 7542 1810, outside UK +91 80 6749 3638;))