Andy Burnham is about to discover that being Prime Minister is a bit like being in a band: the summer tour is fun, but the real gig is in Parliament, where the hecklers are paid to be there. When Parliament returns on Tuesday, the new PM will face the most intense scrutiny of his political life.

Since taking office six weeks ago, Burnham has enjoyed a honeymoon period largely of his own making. Labour's leadership contest timing meant he strolled into Number 10 after the Commons had already clocked off for summer, dodging the usual parliamentary interrogation. Instead, he has been on a 'summer tour' of the UK, appearing on podcasts and unveiling eye-catching policies aimed at the cost of living. But the fun and games end when he faces MPs in a statement on his priorities.

He's faced MPs before, back in the Blair and Brown days, but Tuesday will be his first time on the government front bench in 16 years. His team calls the start 'successful' but admits relief at returning to the 'structure' of parliamentary politics.

The real debut comes Wednesday at PMQs, almost two decades in the making. A packed chamber, hostile opposition, and the week's biggest TV audience - quite a step up from his nine years as Mayor of Greater Manchester. A Number 10 source called it a 'learning exercise' to see 'what works and what doesn't'. Burnham plans a 'tonal shift', bringing more humour to the session. He likes to speak without notes, as he did outside Downing Street, and may do the same at PMQs. His aides are relaxed, even though these weeks could define his premiership. Their mantra? 'Problem solving, not point scoring' - aimed at Conservative leader Kemi Badenoch and others.

Badenoch, meanwhile, is recalibrating. Senior Tory aides say Burnham is a 'different proposition' than Sir Keir Starmer. She's called him a 'people pleaser' who avoids tough decisions - a theme she'll likely repeat. The Tories have flagged three vulnerabilities: defence spending, tax rises, and prisoner early release.

The prisoner row has already given Burnham his first headache. Justice Secretary Alex Norris will make a statement next week on ensuring the killers of PC Andrew Harper aren't released early. Burnham publicly backed Norris to fix it, but officials had warned it's no easy fix. Critics see it as an early test of his decision-making.

Message discipline is the order of the day, especially in the Treasury. The big moment comes on 28 October, when Chancellor John Healey unveils the Budget. After Sir Keir and Rachel Reeves were burned by leaks, Burnham's team is treating Budget security like national security. Speculation about tax rises will dominate Westminster, with Burnham reiterating his 2024 manifesto pledge not to raise income tax, VAT, or national insurance - but hinting at 'room for movement' within that pledge. The Tories smell blood.

The Treasury aims for a Budget that won't spook markets, with themes of 'fiscal discipline' and 'fiscal devolution'. Healey, who quit as defence secretary over funding, must find £4.7bn extra for defence. He won't outline a path to 3% of GDP on defence until spring's Spending Review. A Treasury source insists no one doubts Healey's commitment to national security.

There's chatter that Burnham wants to curb the Treasury's grip, transferring 'local economic growth policy' to his new 'Number 10 North' in Manchester. The Treasury downplays any rivalry.

On foreign policy, French President Emmanuel Macron will visit Downing Street. And Burnham must keep his own backbenchers happier than before - many felt Sir Keir didn't listen. Burnham has met most Labour MPs and plans to be visible in voting lobbies and tea rooms. But with over 400 MPs, there's a divide on priorities amid a tricky financial outlook. A Number 10 source admits the 'public's expectation bar is high and we've got to meet it'.

Also in the news: Burnham refuses to rule out tax rises in autumn Budget; faces unpopularity test over prisons dilemma; unveils plan to get rough sleepers off streets for Christmas. Sign up for our Politics Essential newsletter to keep up with Westminster's inner workings.