Profits of over £3bn ($5bn) are expected to be reported by Barclays for the first half of 2009.
Barclays has announced pre-tax profits of £2.98bn for the first half of 2009.
HSBC is also due to give its latest figures on Monday, with Lloyds and RBS announcing theirs later in the week.
Profits for the year were slightly below analysts' forecasts of more than £3bn, but were up 8% on the £2.75bn it made in the first six months of 2008.
BBC business correspondent Nils Blythe said all the major banks were expected to reveal large potential losses from loans to businesses and households.
The results were boosted by the performance of its investment banking division, Barclays Capital, which saw profits double compared with last year.
But it is thought that booming profits from investment and trading activities will improve the overall figures.
HSBC is also due to give its latest figures on Monday, with Lloyds and RBS reporting later in the week.
Growing losses
Our correspondent said profits were booming again in the so-called "casino banking" activities of the City and Wall street.
While Barclays and HSBC are likely to see the best results, figures from Lloyds and Royal Bank of Scotland are expected to show that they are still struggling.
Banks should watch out that they do not misuse government support - its designed to facilitate lending, not mega pay deals Shadow chancellor George Osborne Crunch time for UK banks
Having picked up some still-successful operations from the wreckage of Lehman Brothers in 2008, Barclays bankers will inevitably see big bonuses.
The Sunday Times reported that investment bankers at Barclays could be paid an average of £250,000 ($418,037) for six months' work.
Both Barclays and HSBC did not accept government bail-outs.
George Osborne, the shadow chancellor, said the Conservatives had been warning about the prospect of "unacceptable" bonus payments from banks which had taken Treasury funds.
He added: "Banks should watch out that they do not misuse government support - its designed to facilitate lending, not mega pay deals.
"Also, the government - who own half the banking system - should realise actions speak louder than words."
Other banks will also have benefitted from trading and investment activities.
But all are expected to reveal growing losses from loans to households and businesses.
Later in the week, Lloyds Banking Group, which took over HBOS at the height of the financial crisis, is expected to report a loss of around £5bn ($8bn).
RBS, meanwhile, is expected to have broken even with a profit of around £1.2bn ($2bn) after reporting the UK's biggest corporate loss of £24bn ($40bn) in 2008.
The scale of bad loans at the banks will also be in focus as the recession leads to more job losses while homeowners and businesses struggle.
And banks are all having to consider how they will cope when the trillions of pounds of support from governments around the world which are currently propping up their industry are eventually withdrawn.
The banks will also feel obliged to show that they have kept to a commitment to increase lending to businesses.
Chancellor Alistair Darling recently urged the banks to play their part in promoting economic recovery and expressed concern that smaller firms are being charged high interest rates.
In the US, big bonus payouts from the likes of Goldman Sachs - less than a year after banks were bailed out by the government - have attracted criticism.
