The British economy grew at its slowest pace in six years in 2018, data showed on Monday, as Brexit uncertainty grips the country and fears grow that Britain could crash out of the EU without a deal.The bleak official figures came as the British government seeks to win more time to secure EU concessions on Brexit that could pass the UK parliament and avert a chaotic split from the bloc on March 29.Businesses are on edge with Britain just weeks away from its scheduled departure from the European bloc after 46 years and still with no firm arrangements in place.Parliament in London last month roundly rejected a Brexit deal Prime Minister Theresa May had sealed with the remaining 27 EU leaders.Monday's figures followed data last week that showed Britain's dominant service sector almost ground to a halt in January."The economy is clearly struggling in the first quarter of 2019 amid serious business and consumer caution resulting from heightened Brexit uncertainties while weaker global growth is also impacting" the figures, noted Howard Archer, Chief Economic Adviser at the EY ITEM Club.Last year, gross domestic product growth stood at 1.4%, down from 1.8% in 2017, the Office for National Statistics (ONS) said. Growth was only 0.2% in the last three months of 2018, the ONS said in a statement."Construction, production and services output fell in the month (of December), the first time that there has been such a broad-based fall in monthly output since September 2012," the ONS said.Britain has been in a state of political turmoil for two months since the Brexit deal was agreed in December.In an incident heavy with symbolism, parts of parliament were cordoned off on Monday after a large piece of masonry fell onto a parked vehicle over the weekend.EU's chief Brexit negotiator Michel Barnier has called for "clarity and movement" from Britain.In an effort to break the impasse, Brexit Secretary Stephen Barclay hosted Barnier for a working dinner at the British ambassador's residence in Brussels on Monday, with concern growing on both sides of the Channel.Speaking after the dinner, Barnier said the talks had been "constructive". "We are clear from our side that we are not going to reopen the withdrawal agreement, but we will continue our discussion in the coming days," he told journalists.Earlier, Barnier said British opposition leader Jeremy Corbyn's proposal for a permanent customs union with the EU was an "interesting" one.Researchers at the IWH Institute in Halle, eastern Germany said a no-deal Brexit could put 600,000 jobs around the world at risk, with Germany the hardest hit.