As the UK's biggest public service department it administers the State Pension and a range of working age, disability and ill health benefits to around 20 million claimants and customers.

[12] In 2012, the department fully subsumed pensions, disability and life events under the DWP name; Jobcentre Plus and Child Maintenance Service remain as distinct identities publicly.

[29] Since at least 2020 DWP has had a policy of cold-calling vulnerable and disabled people to attempt to pressure them into accepting lower benefit claims than they were legally entitled.

[32] The DWP introduced the "Tell Us Once" system in 2011 to enable people to use a single interface to inform the government about a change in their personal circumstances.

Using 'Tell Us Once', departments and agencies like the pensions service, HM Revenue & Customs, the Passport Office and local authorities are informed about a person's change in circumstances in parallel, removing the need for "repeated, unnecessary form-filling".

The Crown Commercial Service states that "cutting administration costs and reducing the overpayments of benefits—usually because of out-of-date records of people's personal circumstances—protected the cross-government savings generated by Tell Us Once, estimated at more than £20 million per year.

[41] The government noted in 2013 that DWP's third-party expenditure was characterised by a number of "complex, high-value contracts".

[43] The department is a major commissioner of external social science research, with the objective of providing the evidence base needed to inform departmental strategy, policy-making and delivery.

During 2012 the department announced records of the number of people born outside of the United Kingdom ("non-UK nationals") claiming work-related benefits from 2011, using data already collated within the department together with those of HM Revenue and Customs and the UK Border Agency[45] (whose duties are now fulfilled by UK Visas and Immigration).

Employment, health and safety, and social security policy are reserved matters of the United Kingdom government.

The Scotland Act 2016 devolved specific areas of social security to the Scottish Government to administer and reform.

A Code of Conduct aiming to "to ensure excellent sub contractual relationships between the top-tier and high performing third sector and other organisations" working for these schemes was established in the department's 2008 Commissioning Strategy.

[42] In August 2015, the department admitted using fictional stories from made-up claimants on leaflets advertising the positive impact of benefit sanctions, following a Freedom of Information request from Welfare Weekly,[50] claiming that they were for "illustrative purposes only"[51][52] and that it was "quite wrong" to pass these off as genuine quotes.

[54] The DWP had fought hard for the figures not to be released, with chief minister Iain Duncan Smith at one point telling Parliament that they did not exist.

Frank Field MP stated in early 2020 that claimants, "will be left at the mercy of online systems that, even now, leave all too many people teetering on the brink of destitution.

"[56] In 2019, the department was found by an independent inquiry to have broken its own rules, in a case where a disabled woman killed herself in 2017 after her benefits were stopped when she missed a Work Capability Assessment because she had pneumonia.

[58] In 2022 the department refused to release data to researchers at Glasgow University who were investigating if benefit sanctions were linked to suicides.