At 54, Jamie Hartzell is on to his third career.

He started his working life making documentaries for the BBC’s natural history studio in Bristol, transformed himself into a property developer and now he specialises in financial investment.

But his career has a common theme: ethics. As a film-maker, he specialised in environmental topics and edited The Vanishing Earth, a programme that looked at the causes of the famine in Ethiopia, and went on to make films for the United Nations.

A philosophy graduate, he fell into the property industry by accident after meeting Andrew King, who had bought a building in Bristol to rent out to charities and campaign groups.

“I moved to London and was working in my attic, making films, which was very tense with small children at home, so I started looking for premises for the film business and bought a building near my house.”

He rented the spare space to a refugee group and the Green Party and borrowed to buy the building next door. “I didn’t realise what I was getting into,” he said.

He and Mr King ended up co-founding the Ethical Property Company, which five years ago moved to the Old Music Hall in Cowley Road, Oxford, having transformed it into modern offices for organisations including Reading Quest, Refugee Resource and Sustrans.

The Ethical Property Company now employs 70 people in 15 centres across the UK, but last year Mr Hartzell changed career once more to set up Ethex funded by charitable trusts with help from the Big Lottery Fund.

Ethex is a website featuring different ethical investments – from Golden Lane Housing, providing homes for people with learning disabilities, to Oikocredit, lending to small business people in Africa.

Ethex also offers services to member businesses and runs the Westmill Solar Coop, based near Faringdon.

With charges to investors and to businesses, Mr Hartzell expects Ethex to be breaking even in the next few years.

Recently he appeared on the BBC Radio 4’s Moneybox Live, and was featured in The Guardian, Evening Standard and radio features as part of Ethical Investment Week.

Ethex says Oxford is fifth best city for ethical investment, with hotspots in Summertown, Jericho, Osney, Appleton, Cumnor and Hinksey Park.

Mr Hartzell said ethical investment was popular in areas with highly-educated, independent-minded people.

“Oxford punches well above its weight compared with towns which are much wealthier,” he said.