A University tutor has produced a formula which suggests May 18 is the optimum date for life-changing resolutions.

Dr Cliff Arnall, a part-time tutor in the Centre for Lifelong Learning, was challenged to find the ideal day for positive thinking.

He devised the formula M x O + Bh (H+R) x S to discover that New Year resolutions stand a better chance of success if they are made on May 18.

Under the formula M stands for motivation and O for opportunity while Bh is bank holiday proximity.

The H in the second half equals increasing hours of daylight, while R equals reflection time and S, simply success.

Dr Arnall, a specialist in happiness, motivation and confidence, hit headlines around the world in January with a formula for the most depressing day of the year — January 24.

His latest formula results from a challenge by the Get On campaign, run by the Department for Education and Skills under the Government Skills for Life strategy.

Dr Arnall said: "If you've got your heart set on a promotion at work or are fed up struggling to work out change in the supermarket, May 18th is the day to take the first step."

From Cardiff University