Almost half of men are failing to take up their right to two weeks paternity leave after the birth of their children, mainly because they cannot afford to, new research has revealed.

Two out of five men are afraid to ask for flexible working arrangements because they think it would harm their career prospects, a widespread study of 4,500 parents in Britain also showed.

The study, by the Equalities and Human Rights Commission, revealed many fathers are working long hours and struggle to balance work and family life.

Men want to take a more active role in caring for their children, but two out of five admit they do not spend enough time with their sons or daughters.

Most of the fathers surveyed said the availability of flexible working was important when looking for a new job.

Fathers taking paternity leave are paid a statutory rate of £123 a week, but the commission argued they should receive 90 per cent of their actual pay.

It has also called for four months of parental leave that can be taken by either mother or father, eight weeks of which would be at 90 per cent of pay.

Andrea Murray, acting group director of strategy of the Equality and Human Rights Commission, said: “It is clear that today's families require a modern approach to balancing work and childcare commitments.

“Fathers are telling us they are not spending enough time with their families and want to take a more active role in shaping the lives of their children.

“We have spoken to parents, employers, unions and leading academic experts in the field, and we believe that our policies lay out a road-map to 2020 which will put Britain ahead of the curve in terms of modern working practices.

“Two-thirds of fathers see flexible working as an important benefit when looking for a new job. This highlights an opportunity for British businesses to use flexible working as an incentive for attracting and retaining the most talented of employees.

“Some companies which have adopted forward-thinking policies towards families are reporting increased productivity, reduction in staff turnover, reduced training costs and an ability to respond better to customer requirements.”

Six out of 10 fathers said they work more than 40 hours a week, adding that was too much.