JD Wetherspoon chairman Tim Martin has said the “jury is still out” on the group’s trial of a pizza offer, admitting he has his doubts as to whether it will be profitable.

The trial is currently ongoing in c150 pubs, offering a choice of six pizzas priced between £6 and £9, but Martin said the results were still not conclusive.

However, he said the decision to test the idea was at the heart of JDW’s business model, and one of the reasons why the company continued to out-perform its peers.

He said: “We listen to our people, and they listen to their customers. We have been trading for a long time and any success we have had has been over hundreds, maybe thousands, of small initiatives, that have mostly come from staff.

“We have being paying staff bonuses since 1998 and that has helped us to have slightly higher retention.

“If you were to boil it down to one reason why we continue to trade well I’d say it’s a people thing. Having tried to adopt the ideas of the people who work in the pubs and who are closest to the customers. That’s given us a competitive edge.

“Very prosaic things make the difference in the long run. It’s the aggregation of marginal gains, as Dave Brailsford was quoted as saying before he fell out of favour.”

On the pizza offer, he said: “The jury is out on pizza. It’s adding another level of complication and the question is whether that is justified by sales. Pizzas certainly have their advocates within the company.”

On the supply issues that have bedevilled the industry over the past few months, he said: “The Matthew Clark situation could have been a big issue but in the end it had minimal impact because we were holding a lot of stock. Stocking levels are now pretty much back to normal levels.

“We have traded with Matthew Clark for 20 years and we still are. They have done a good job for us and others and we wish them every success.”

On the impact of the company widely publicised withdrawal from social media, he said: “Social media can work for some companies but there is a market for pubs like ours, which don’t advertise and which don’t have music or entertainment to provide a bit of an oasis away from that. As Plastic Betrand said – ‘Ca plane pour moi’ (It works for me). I bet you don’t quote me on that.”