Pensions, private medical insurance and holiday trading are the most popular benefits to be taken up by employees through their flexible benefits schemes, according to research from Aon Consulting.

Its UK benefits tracker, which monitors the take up of benefits included in its clients' flex plans, found that 79% of employees were members of the employer's pension schemes between July 2007 and January 2008, while 14% elected to make additional voluntary contributions into their pensions.

The tracker covers up to 60,000 employees through 50 schemes from employers varying in size from 200 to 2,000 staff.

The second most popular benefit in this period was private medical insurance, chosen by 32% of employees, making it significantly more popular than in previous years.

Holiday trading came in as third, appealing to 17% of employees. Of these, 38% elected to sell holiday, while 62% opted to buy extra entitlement. This is a marked shift from previous years, when the ratio had been 80:20 in favour of buying holiday.

Dental insurance, childcare vouchers, income protection and retail vouchers or discount cards also made it into the top ten flexible benefits options. Discounted retail vouchers is a new entry.