MPs traded blows about their second jobs today - with Tory Geoffrey Cox under fire for his extraordinary £1million a year legal earnings.

Politicians are pointing fingers at each other over their paid sidelines in the wake of the bitter row over Boris Johnson's abortive bid to save ally Owen Paterson from punishment for lobbying.

The PM said this morning that he expected outside income for MPs to be 'looked at' - with the standards committee set to make recommendations before Christmas.

Labour is pushing for paid directorships and consultancy roles to be banned - although Keir Starmer says nurses and other professions should be allowed to continue.

But the Tories have pointed out that a number of Opposition MPs also have some outside earnings alongside their salaries of around £82,000 a year. 

Mr Cox, an eminent QC, has long been one of the biggest earners in the Commons. 

In the latest register of interest, the Torridge and West Devon MP revealed that from this month he is receiving £400,000 a year plus VAT for 41 hours' work a month as Consultant Global Counsel to Withers LLP.

That is actually a reduction on the £468,000 he was receiving for doing 48 hours in the same role in the previous year.

Mr Cox's entry includes some £570,000 more income for legal work. The register notes that 13.5 per cent goes towards the costs of his legal chambers. 

There is no suggestion that Mr Cox has broken any rules.

But Labour MP Karl Turner tweeted: 'How does ⁦@Geoffrey_Cox⁩ find time to do his job as a constituency MP, keep his own legal practise going from his chambers and is a consultant to @WithersLLP earning 400K plus VAT p/a as an advisor.' 

Asked about the idea of curbing second jobs on a visit in Northumberland today, Mr Johnson said: 'I think that all those kinds of things are issues that the Speaker's panel – whatever he sets up – is going to have a look at.'

Earlier, Trade Secretary Anne-Marie Trevelyan was asked on Sky News whether MPs should be allowed to have second jobs.

She said: 'I think the question of whether MPs having jobs that involve lobbying, I think, perhaps should be looked at again.

'Across the board, I don't think we should have a removal of the ability to maintain or have a second job because it brings a richness to our role as Members of Parliament as well as the work we do day to day with our constituents.'

The Register of Members' Financial Interests shows 34 MPs have been declaring payments for consultancy or advisory work.

They include Owen Paterson, who was found by the Standards Committee to have engaged in 'egregious' lobbying on behalf of two companies which paid him a combined total of more than £100,000 per year.

He has now resigned from the Commons and said he is stopping his consultancy duties. 

There are no rules against MPs being paid for advising external businesses, provided they record it in their register of interests, but they must not lobby the Government on behalf of those businesses.