Colourful Lord Bath has given his heir the lions, the gorge, but not the wardrobe.

The 7th Marquess of Bath, known for his penchant for psychedelic clothing, has handed Longleat Estates Ltd – the firm that owns Cheddar Caves & Gorge and his famous safari park – to his eldest son, Ceawlin.

Alexander Thynn announced: "Despite the economic doom and gloom, 2009 had been a remarkably good year for both Longleat and Cheddar with visitor numbers on a par with 2008 and turnover up. I feel that now is a good time for me to retire and for my son, Ceawlin, to take over as chairman of the company."

The 78-year-old, known for having at least 73 "wifelets" or mistresses, will still live in iconic Longleat House and remain active in some areas of the business, but felt it was "the right time for me to retire to my chair and slippers and watch as Ceawlin brings new life into this very special place. I'm looking forward to a future where I can sit back and let Ceawlin do the work!"

Lord Bath is 359th in the Sunday Times Rich List 2009 with an estimated £157 million.

The 36-year-old Viscount Weymouth thanked his father and mother for their work in the family business and said: "Longleat and Cheddar Caves are among the top tourist attractions in the UK and it is my hope that I may follow on in the footsteps of my remarkable father and take both attractions very firmly forward."

Ceawlin Henry Lazlo Thynn is named after a dark ages king of Wessex and uses his father's subsidiary title, Viscount Weymouth, as his courtesy title.

As a teenager he cleaned the toilets at Oscars Nightclub on the Longleat estate to earn his pocket money and attended a local comprehensive school on the insistence of his father. However, he used his trust fund to pay for his own private sixth form education at the exclusive Bedales School before being expelled after a year for smoking cannabis.

Although less eccentric than his mural-painting father, Viscount Weymouth was recently fined £1,500 for annoying neighbours by playing loud music and operating an antique printing press in his London home at 4am.

He blamed the incident on partial deafness caused after surviving a terrorist bomb blast 14 years ago in a Delhi hotel, killing 17 people, including his girlfriend and best friend.

He is a financier and managing director of Moscow-based Lion Trust Development Management, which builds mid-market hotels in Russia.

Hugh Cornwell, director of Cheddar Caves & Gorge, praised Lord Bath's stewardship of Longleat.

"I know that both at Longleat and Cheddar it is a far stronger business than when he took over," he said.

"Visitor numbers grew from about 4,000 to 7,000 a year and that enabled him to do all sorts of renovation on the fabric of Longleat House."

Viscount Weymouth is no stranger to Longleat Estates Ltd, working in the background for about six years.

Mr Cornwell continued: "Lord and Lady Bath standing down as directors and Ceawlin becoming chairman is an evolutionary process. We do not expect any dramatic changes."

It was also announced a new chief executive for Longleat Estates Ltd was needed, but the Cheddar Caves & Gorge director joked: "I have reached the level of my own incompetence to apply myself."

Mr Cornwell turned 61 last month, but said he still has a lot to do during his remaining years at Cheddar Caves & Gorge and still had a vision of a cable car system; a single, convenient car park instead of several throughout the gorge, narrower roads and a toll road system for visitors to reduce traffic and pay towards conservation.

He said: "Cheddar Caves & Gorge is a lot more complex than when I started 22 years ago. I find the people and place fascinating, it still pushes all my buttons."