Media captionThe chancellor opened his 2016 Budget with comments about the UK economy
Experts are due to give their verdict on George Osborne's ability to hit his fiscal targets after the chancellor unveiled a Budget featuring a sugar tax and gloomy economic forecasts.
The influential Institute for Fiscal Studies will scrutinise the chances of the deficit being cleared by 2019-20.
Mr Osborne said his Budget "puts the next generation first".
But Labour attacked the decision to save billions by 2020 with cuts to disability payments.
The Opposition did give a cautious welcome to the the chancellor's headline-grabbing announcement, raising £530m with a tax on the sugar content of soft drinks.
Other key Budget measures included:
Growth forecasts cut for the next five years and £3.5bn in extra public spending cuts by 2020
Mr Osborne missed his target of cutting debt as a share of GDP
A 2% increase in tax on cigarettes and 3% on rolling tobacco from 18:00 GMT, but beer and cider duty will be frozen as will the levy on whisky and other spirits
Plans for a longer school day in England
The rate at which workers start paying the top rate tax is to be raised from £42,385 to £45,000, with the tax-free personal allowance raised to £11,500 and corporation tax to be cut to 17% by April 2020
On savings, the ISA limit will be increased to £20,000 a year for all savers, and lifetime ISAs with a 25% bonus will be introduced for young people
An extra £700m for flood defences - to be paid with a 0.5 percentage point increase on the tax on insurance premiums
The higher rate of Capital Gains Tax is being cut from 28% to 20%
Despite warning of a "dangerous cocktail" of global risks, Mr Osborne told MPs he was still on course to eliminate the deficit by 2020, by making extra spending cuts.
But BBC political correspondent Alex Forsyth said independent analysts were warning this could be "very difficult" and saying the chancellor was "shuffling money around" to meet his self-imposed rules.
BBC experts analyse the Budget
Laura Kuenssberg and Kamal Ahmed
Political editor Laura Kuenssberg: Can Osborne defy political history?
Economics editor Kamal Ahmed: Osborne stakes reputation on 2020 surplus
Business editor Simon Jack: Small businesses are the winners
Political correspondent Iain Watson: Corbyn gets mixed reviews
Mr Osborne is also facing a rebellion on the "tampon tax" from MPs across the House of Commons.
Currently VAT is charged at 5% on sanitary items, the lowest rate allowable under EU law.
But over 300,000 people have signed a petition calling for sanitary items to be exempted from tax altogeth