Tomorrow (March 16th), Chancellor George Osborne will proudly pose with that iconic red briefcase in front of 11 Downing Street before making the short journey to the House of Commons to deliver his eagerly-awaited Budget to a rowdy and excitable crowd of MPs.

As Osborne again takes centre stage, he will be acutely aware that this could be his defining – or even his last – Budget. George Osborne, like Prime Minister David Cameron, has pretty much staked his political future on remaining in the EU. A vote to leave the EU in the upcoming referendum would catapult Osborne’s rival, Eurosceptic Boris Johnson, into pole positon of replacing incumbent PM, David Cameron, to become the next Conservative leader.

Rather than affording Osborne the opportunity to announce unpopular and radical measures, this Budget will be very much framed in the context of the EU vote. And the looming referendum would have been uppermost in the Chancellor’s mind when recently staging a dramatic U-turn on plans to announce either an Isa-style pension system or a flat rate of tax relief in the Budget.

These radical changes to pension tax relief that the Chancellor was until recently expected to announce were met with strong opposition by some Conservative MPs, as well as the business community, who claimed they would have amounted to a tax raid disproportionately affecting middle earners and potentially triggering a retirement crisis.

Furthermore, David Cameron was reportedly concerned that those Conservative MPs backing the campaign to leave the EU could use the Budget as an opportunity to attack pro-EU Chancellor George Osborne. According to reports, Cameron warned his Chancellor not to go too far with pension reforms so as to not antagonise those Conservative MPs wanting to leave the EU.

Faced with the prospect of a rebellion within his own party ahead of a crucial vote on the country’s membership of the EU, Osborne decided not to go ahead with his politically toxic pension reforms.

In addition to these considerations, Osborne would have been very much aware that the Budget — while making for great political theatre — also has the power to make or break the political ambitions of incumbent Chancellors. And the current Chancellor is an ambitious politician considered to have an eye on the top job at Number 10. Osborne need only look back to the disastrous “Omnishambles” Budget of 2012 and the Government’s embarrassing U-turn on the deeply unpopular “pasty tax” and “caravan tax” to remind himself of how politically damaging Budget Day can be. So Osborne will want to use Wednesday’s Budget to present himself as a credible future Conservative leader and potential Prime Minister.

Meanwhile, middle income earners would no doubt have breathed a deep sigh of relief at news of the pension tax relief climb down. And large numbers of advisers would have welcomed Osborne’s U-turn too. The latest report by CoreData Research on the pension industry reveals that over three in five advisers are against the idea of an Isa-style pension system and nearly half are opposed to a flat rate of tax relief.

But it is perhaps too early to be popping the champagne corks. With the Chancellor likely to revisit the tax relief issue after the vote on EU membership, Osborne’s change of heart is more a stay of execution than a permanent U-turn.

Important changes to the pension landscape are still expected to be announced in the Budget, with options on the table including a possible reduction in the annual and lifetime allowance and restrictions placed on salary sacrifice. Further down the road, those saving for retirement could be hit by adjustments to defined benefit, or final salary, pensions and the Government could also introduce new regulations around workplace pension master trusts.

The proposed changes to pension tax relief come on the back of far-reaching reforms to the pension sector as a whole. From auto-enrolment to pension freedoms, the industry has recently undergone huge upheaval. This is primarily because it lies at the forefront of Government efforts to reduce the strain on public finances, foster a widespread savings culture and defuse the demographic time bomb caused by an ageing population.

And advisers clearly feel these reforms are necessary. The CoreData report, based on a study of 429 advisers, reveals that 83% broadly back the recent overhaul of the pension system. However, there is a mixed picture in terms of individual reforms. A vast majority of 83% think the new pension freedoms provide business opportunities and a similar number (82%) support the introduction of a cap on excessive early exit fees. But advisers are less positive on the prospects afforded by auto enrolment, with just 21% agreeing it offers big growth potential.

And the report also reveals widespread concern about the UK’s demographic time bomb, with 82% of advisers saying the government is not doing enough to address the country’s ageing population.

Crucially, the CoreData study finds that 67% of advisers regard attracting clients close to retirement as a priority. So staying on top of pension regulations amid this ever-changing and complex landscape will be vital. As such, all eyes will be on George Osborne tomorrow to see if he can deliver some much-needed good news for pension savers in what will be one of the most political Budgets in years.