Following the deal, David Clemson, who first joined the business in 2008, will continue in his role as managing director.

Founder Michael Wright will maintain an interest in the business as a non-executive director and “significant” shareholder.

The deal comes following strong growth for Riviera in the last few years during which time it delivered turnover growth of more than 20% per annum while in 2014 it carried more than 115,000 passengers.

Wright said: “I am delighted to welcome Phoenix as a new investor in Riviera. Phoenix is very experienced at partnering with founder-owned businesses.

“Together, we shall continue to focus on providing exceptional service for our loyal customers, developing our successful portfolio of tours and river cruises, and creating opportunities in the business for staff at all levels.”

Clemson added: “I am very excited that Phoenix is investing in the business. They have strong experience of the leisure sector and, most importantly, it will be business as usual as we move into the busy booking season in January.”