According to the Daily Telegraph, the Armed Forces should recruit more part-time soldiers to help Britain prepare for conflict and natural disasters, the FR20 review has concluded:
The study, led by Gen Sir Nick Houghton, the Vice-Chief of the Defence Staff, will also urge a rethink on plans by ministers to cut the TA's budget.
The Territorial Army, and its Navy and RAF equivalents, should be asked to shoulder more responsibility in future operations, the review will say.
The six month review, ordered to assess how the services will operate in the 21st century, will call for the part-time soldiers to be used more readily in war, terrorist attacks and any natural disasters that hit Britain.
The Future Reserves 2020 study, due to report back in the summer, will reportedly advise a balance between reserve and regular forces that reflect Britain's closest allies, such as the United States and Australia.
In those countries the proportion of part-time soldiers, sailors and airmen is higher.It will conclude that the ratio between numbers of part-time and full-time troops, which currently stands at 15:85, needs to be increased.
This compares with a 50:50 split between reservists and regular forces in America and a 40:60 divide in Australia, Canada and New Zealand, The Times reported.
It will also contain proposals to deploy company and potentially even battalion-size reserve units on operations such as in response to a flood in Britain or a terrorist attack.
The recommendations in the report, to be submitted to the Prime Minister by the end of June, marks a reversal of plans drawn up inside the MoD to cut the already diminished number of reservists.
During the negotiations leading up to the Strategic Defence Review, Liam Fox, the Defence Secretary, was shown plans to reduce the number of reservists by a third.
The Daily Telegraph reported last year that a MoD paper that was circulated in Whitehall had set out three options for TA numbers, all involving substantial cuts.
Even the most modest cut TA numbers were thought to be reduced to around 24,000.
A "central" option was discussed would leave the TA with approximately 14,000 soldiers. The most radical would see TA numbers fall to barely 9,000.
The TA currently has around 35,000 soldiers, but Ministry of Defence officials say several thousand of them are "dead wood" who cannot be deployed on front line operations.
Running the TA costs almost £500 million every year and each reservist soldier costs more than £15,000, significantly more than each Royal Navy and RAF reservist.
The review is expected to show that over a five-year period a full-time soldier, with their housing, pension and welfare expenses, is three times more expensive to maintain and deploy than their part-time equivalent.
Figures show that the number of TA reservists is declining after three years of underfunding, in what one source described as "withering on the vine".
Gen Houghton is conducting the review with assistance from Julian Brazier, the Conservative MP, who was asked by Mr Cameron to help to conduct the review, and the retired Lieutenant-General Sir Graeme Lamb.
"At the end of this process we want to end up with a much better relationship between the regular and reserve forces and with the reservists feeling that they are better appreciated," said Mr Brazier, a former TA officer.
"I do not think you are going to see the overnight slashing of training and personnel numbers that you have seen in the past.
"The size and scale of the reserves will depend upon where the Prime Minister decides to set the balance. I think what we will be announcing will please reservists."
General Lamb added to the paper that under current resources, initial manpower available in a catastrophe "will start to run out of gas pretty quickly".
"While we have the ability to export our force, I am not sure the resilience in homeland security is as comprehensively covered as we should feel comfortable with given all the issues such as cyber security, unnatural or natural disasters, and the nature of how extremism, radicalism and terrorism can be brought to bear," he added.
An MoD spokeswoman said that reserve forces "are, and will remain, an essential part" of the Armed Forces.
"The Future Reserves 2020 study is about ensuring we have Reserve Forces that meet our future needs," he said.
"The study is seeking opinions from across the Defence community and will report back in the summer.
"It would be wrong to speculate on the potential outcomes of the review while it is still ongoing."
- Daily Telegraph source article, by Andrew Hough - 'Armed forces should recruit more part-time soldiers' review urges
- British Army Website - Future Reserves 2020 (FR2020) - The recommendations of the FR20 Commission set up by the Prime Minister to examine the future shape and role of the UK's Reserves Forces have been presented to the Prime Minister. They are scheduled to be announced to Parliament in July.