Chancellor George Osborne has unveiled the biggest UK spending cuts since World War II.
Shadow chancellor Alan Johnson, has called the review a "reckless gamble with people's livelihoods" which risk "stifling the fragile recovery" - a message echoed by the SNP, despite smaller than expected cuts in Scotland.
BBC News website readers who receive benefits have been reacting to news of the cuts.
Nigel, Bethnal Green, London
When I woke up this morning I was full of fear.
I appreciate that the money has to come from somewhere but it seems wrong to be taking it from those who need it the most. I think they've gone about it the wrong way - they're acting like a bull in a china shop.
I get Incapacity and Disability Living Allowance (DLA) and income support, which is £2 a week, as well as housing benefit.
I started working when I was 16 and only stopped in 2006.
After my partner passed away, I broke down. I lost everything I owned. I am trying to make a new life for myself but I am struggling.
I am long-term HIV-positive and as an older person, I should be really looking after my health but some days I can't afford to eat or turn on the heating.
In addition, because of the NHS cuts, I can't get counselling any more.
It is difficult to see the future beyond this now.
The money is in the wrong place - I don't understand it. I don't see a way out of it. I'm terrified of the door bell ringing or a knock at the door in case there's something else I have to pay for that I can't afford.
They seem to be targetting the people who are really poor. But the big bankers and those who have the money, they are all fine. They are not facing any cuts.
£10 to me is the difference between having a life and not.
But to them it's nothing.
I voted for the Liberal Democrats, so I now feel very betrayed by them.
Whenever you hear something more coming out you just think oh what next? If they keep on cutting we'll be in the poor house.
They obviously don't want us here. It's like we're not good enough. They don't want us in their perfect little world.
I know there are those who abuse the system and, yes, I do think that it is right that they are stopped, but it is not fair for those who are genuine.
I've been on Incapacity since I was 21. I'm now 48. I was born disabled.
Although initially no-one could pinpoint what was wrong with me. I was diagnosed first with tuberculosis, then arthritis, then hypermobility syndrome, then Ehlers-Danlos syndrome. Accompanying this I have several other health concerns.
Most of my problems are hidden conditions, so if anyone looks at me they think there is nothing wrong with me. Many times I've had assessments by so-called medical professionals, and on at least three occasions now, I've lost my benefits and faced up to 18 months of fighting and struggling to get it back.
It is exhausting for anyone, but when you are struggling with ill health on a daily basis, it is the last thing you need. The mere mention of benefit reforms turns my stomach into knots.
They said I was entitled to benefits for life but then they review it and they might say they'll now take it away from me. So, I don't know what will happen in the future.
My husband works but I have to rely on benefits. My husband only earns £15,000 a year. We can't save. I also have two teenagers who I get child benefit for.
If they take this away, then I just don't know how our family of four is going to survive. I mean our rent is over £600 a month.
I go through enough stress as it is but all of this just adds to it. Sometimes I think I can't go on. There is only so much I can take, and personally I've had more than enough.
I'm not looking for an easy life lounging around on benefits, I'm looking for ways of developing my interests to keep my mind active when my body lets me down. I've been told I'm unemployable, why won't the benefits agency accept that? Instead of that, they want to make us jump one hurdle after the other, continually, until we expire.
Nothing like flogging a dead horse.
Paul, Leeds, UK
I just got a letter back this morning, after my medical assessment last week, and what they said is pretty good news for me as they say that I will get my benefits up until 2012 and so it's worked out quite well for me.
I'm still not 100% sure if the cuts today will affect me but I hope not.
I think they're being very ruthless. There are a lot of people who are genuinely suffering and I'm a little worried that people like myself are going to be pushed down further into the poverty line.
I only get Incapacity Benefit. I have been on it for three years because I have cervical spondulosis of the spine and calcified tendinitis in both shoulders. Before that, I worked constantly for 30 years.
The financial side of things is very difficult but I just cut my cloth accordingly. I am worried though that the cost of living will rise and then I will be in a worse state.
There's nothing as far as I am concerned that can be seen as positive to being on benefits. If anything, there's an awful lot of negatives.
I would like more clarity about what they are actually going to do with people like us because they seem to be wrapping up everything in a lot of political speak which is difficult to understand.