Four out of 10 British managers have not yet booked a summer holiday due to excessive workload, job insecurity and financial uncertainly.

Although British summertime is now fully underway, research from the Chartered Management Institute (CMI) shows 33% of managers who haven't yet taken a holiday, would rather swap it for cash.

And for those who do manage to get away from the office, one in five find it hard to ‘let go' - 72% worry how colleagues will cope in their absence as well as clients and pressing deadlines. More than half (51%) will check emails while on holiday and 44% will check voicemails.

In spite of this 89% encourage their teams to take full holiday entitlement.

Ruth Spellman, chief executive of the CMI, said: "It is understandable a heavy workload and the prospect of returning to a large amount of emails and outstanding tasks can deter people from taking time off, but holiday has a positive impact on staff well-being and boosts productivity."

The CMI is launching campaign to declare an amnesty until 12 July - during which time it is urging managers to book time off.