Britain's economy will grow far stronger than expected this year, Finance Minister Philip Hammond said in a budget update on as the government prepares to trigger Brexit.

Conservative Prime Minister Theresa May has vowed to activate Article 50 of the EU's Lisbon Treaty in the next three weeks, sparking a painful two-year divorce process — and tense talks over the terms of Britain's departure from the European Union.

"As we start our negotiations to exit the European Union, this budget takes forward our plan to prepare Britain for a brighter future," Hammond told parliament as he unveiled a series of measures, including new investment for British schools, as part of the government's latest tax and spend plans.

Hammond, called "Spreadsheet Phil" by fellow Conservative lawmakers for his dry delivery, was viewed as rather uninspiring by the British media and financial analysts when he gave his first budget statement in November.

"I turn now … to the (growth) forecast. This is the spreadsheet bit, but bear with me because I have a reputation to defend," Hammond joked in reference to his nickname.

With UK activity performing better than expected following its shock June 23 referendum in favour of Brexit, Hammond predicted gross domestic product growth would come in at 2.0 percent this year, much higher than the government's previous 1.4-percent GDP forecast.

As a result, the nation would borrow far less than expected this year.

But highlighting the uncertainty surrounding the UK economy as the country prepares to quit the EU, the 1.4-percent 2017 growth prediction given in November had itself been a sharp downgrade on a prior estimate of 2.2 percent.

GDP growth would stand at 1.6 percent next year, down slightly on a prior official estimate of 1.7 percent. Hammond also downgraded forecasts for 2019 and 2020.

Britain meanwhile stands on the cusp of triggering Article 50 by the end of March.

"Today, we reaffirm our commitment to invest in Britain's future, and we embark on this next chapter of our history confident in our strengths and clear in our determination to build a stronger, fairer, better Britain," Hammond insisted on today.

The government confirmed plans to pump more than 500 million into Britain's education system, building new schools and renovating others.