About one in five working-age families in Liz Truss’s own constituency would lose out by hundreds of pounds on average if real-terms benefit cuts go ahead, a charity has warned.

New research from the Joseph Rowntree Foundation (JRF) shows that some 21pc of working-age families in Ms Truss's South West Norfolk seat would be affected by a decision not to raise benefits in line with inflation.

Her constituency includes some significant areas of deprivation in Thetford and the Fens - but they are not the only communities that would be badly hit by the move.

The impact is similarly significant across the rest of the county, with some 78,153 households in Norfolk - comprising about 22pc of working-age families - currently reliant on means-tested benefits.

Ms Truss's government is currently deciding whether or not to instead raise benefits in line with the smaller average increase that wages have seen.

In Great Yarmouth, represented in parliament by justice secretary Brandon Lewis, the percentage of working-age families on benefits rises to 34pc, the highest in the county.

Work and pensions secretary Chloe Smith is reported to privately oppose a real-terms cut to benefits - with some 23pc of people in her Norwich North constituency on benefits.

The government has not yet reached a decision on the question, but Katie Schmuecker, the JRF’s principal policy adviser warned them: “Politicians should think long and hard about the impact of withholding hundreds of pounds from thousands of families in their constituencies when the basic rate of benefits is already at its lowest in real terms for 40 years and prices are sky-high.”

A Department for Work and Pensions spokesperson has said: “The secretary of state commences her statutory annual review of benefits and state pensions from late October using the most recent prices and earnings indices available.”

Despite the energy price guarantee, brought in by the Truss government to ensure a typical household does not pay more than £2,500 a year on their energy bills, polling conducted by the petition website 38 Degrees has shown there is a high level of anxiety among voters over the cost of living.

In Norwich South alone - the constituency of Labour MP Clive Lewis - some 62pc of people are estimated to fear they won’t be able to afford their energy bills, with 32pc fearing they will be homeless in a year’s time, and 37pc fearing they will have to resort to food banks within the same timeframe.

The percentage of working-age households on benefits in each Norfolk constituency is as follows:

Broadland - 16% (6,198 out of 37,895)
Great Yarmouth - 34% (13,293 out of 38,639)
Mid Norfolk - 18% (7,393 out of 40,378)
North Norfolk - 20% (6,484 out of 31,738)
North West Norfolk - 23% (8,741 out of 37,250)
Norwich North - 23% (9,029 out of 39,025)
Norwich South - 23% (11,432 out of 50,166)
South Norfolk - 16% (6,873 out of 43,859)
South West Norfolk - 21% (8,710 out of 40,897)