IT is not pantomime season just yet but, watching Chancellor Philip Hammond delivering his Budget, it was difficult to escape the notion that someone in the audience should be shouting: “It’s behind you.”

The “it” would not have been a reference to the divided Conservative Party sitting behind Mr Hammond. Rather, the “it” refers to something which is very important from an economic perspective and surely deserved more than the fleeting attention it received from Mr Hammond.

The spectre that was looming behind the chancellor and his divided party throughout his protracted Budget speech was, of course, Brexit.

There were some signs that Mr Hammond was aware of the spectre’s presence, albeit these were in euphemistic references as the chancellor delivered a Budget that assumed there would be a Brexit deal.

While making plain his confidence that a no-deal scenario would be avoided, Mr Hammond did at least talk about planning for “all eventualities”, including, if the economic or fiscal outlook changed “materially in-year”, reserving the right to “upgrade the Spring Statement to a full fiscal event”. Or what many people would call an emergency Budget.

However, aside from these references, his tone was surely surprisingly upbeat, with a suggestion that the sun would be shining on a post-Brexit Britain as long as it reached a deal on its future relationship with the European Union.

The independent Office for Budget Responsibility’s forecasts, published yesterday to accompany the chancellor’s latest measures, make a similar assumption about a deal.

However, the OBR growth forecasts seem out of kilter with Mr Hammond’s upbeat and pun-filled address.

And it is important to observe the OBR’s warnings about the impact of a no-deal Brexit.

While not factoring in such a scenario in its central forecasts for UK economic output, borrowing and debt, the OBR said: “A disorderly one [Brexit] could have severe short-term implications for the economy, the exchange rate, asset prices and the public finances. The scale would be very hard to predict, given the lack of precedent.”

Mr Hammond focused on the OBR’s upgrading of its growth forecast for 2019 from the 1.3% it had projected in March to 1.6%.

What he did not highlight was the fact that the OBR had cut its forecast of UK growth this year from 1.5% in March to 1.3%.

The UK economy grew last year by 1.7%. This was its weakest expansion since 2012, and was well adrift of eurozone growth of 2.5%.

Mr Hammond talked about a Budget that “paves the way for a brighter future”.

And he waxed lyrical about opening a “new chapter in our country’s economic history”, looking confidently to the future, and setting a “course for where this remarkable country will go next”.

Back in August 2013, Bank of England Governor Mark Carney noted in a speech that the UK’s historical average annual rate of growth was about 2.75%. The UK economy has been way adrift of this annual expansion rate in all but one year since the Conservatives came to power in 2010. Even on the basis that a no-deal scenario is avoided, the OBR projections underline just how far adrift of this former average the UK will be, as far into the future as the forecasters’ eyes can see.

The OBR predicts growth of 1.4% in each of 2020 and 2021. It sees expansion of 1.5% in 2022 and, even as far out as 2023, forecast growth is only 1.6%. This is on the basis of a deal being struck in the turbulent Brexit negotiations, and the weak growth projections underline the challenges facing the UK in the wake of its departure under any circumstances from the EU.

The OBR notes the country’s average quarterly growth rate has slowed from 0.6% between 2013 and 2015 to 0.4% since the beginning of 2016, “taking the UK from near the top of the G7 growth league table to near the bottom”.

It declares: “Notwithstanding potential future revisions, the referendum vote to leave the EU appears to have weakened the economy. The fall in the pound has squeezed real household incomes and consumption, while providing only a modest boost to net trade. Meanwhile, uncertainty regarding the Brexit negotiations appears to have dampened business investment, by more than earlier data suggested.”

All of this seems at odds with Mr Hammond’s enthusiasm about the new chapter being opened by the “remarkable” UK.

Scotland has recorded faster growth so far this year than the UK as a whole, assisted by the oil and gas sector’s partial recovery. Figures published last month by the Scottish Government showed economic output north of the Border grew by 0.5% quarter-on-quarter in the three months to June. This exceeded expansion of 0.4% in the UK as a whole during the same period.

In the first quarter, the Scottish economy grew by 0.4%. This was four times the corresponding UK-wide expansion rate of 0.1%.

Mr Hammond made a big deal of the OBR having, since March, reduced its net borrowing forecasts for the UK in coming years.

That said, net borrowing is projected to rise from a substantial £25.5bn in the current fiscal year to next March to £31.8bn in 2019/20. It is projected at £26.7bn in 2020/21, before falling to £23.8bn in the following fiscal year. Net borrowing is projected at £20.8bn in 2022/23 and at £19.8bn in the following fiscal year.

Public sector net debt is projected to rise from £1.779 trillion at the end of March this year to £1.896 trillion by the close of the 2023/24 fiscal year. This is a rise of about £117bn.

It is interesting to note that public sector net debt is now forecast at £1.851 trillion in March 2020.

In the spring 2016 Budget, before the Brexit vote, the OBR was forecasting that at March 2020 public sector net debt would stand at £1.725 trillion. This is £126bn less than the figure now projected, something many people may not have gleaned from Mr Hammond’s attempt to portray the Conservatives as a party of fiscal responsibility.