The merger, which takes effect from 1 April 2016, will create an international association with 1,201 partners, 8,990 professional staff and 375 offices in 88 countries.

Morison International was ranked at number 25 in the 2015 Accountancy annual survey of the top 25 international networks and association, with revenues of $779m in 2014. All the other top  25 associations posted revenues in excess of $1bn, suggesting the merged association is likely to retain the same position.

Sir Michael Snyder, chairman of KSi, said: ‘After overseeing 26 years of year-on-year growth and record levels of business referred around the world, this merger provides a greater footprint for KSi to pursue new opportunities, build stronger connections for clients and ultimately enhance our service offerings.’

KSi said the merger provides the association with a ‘solid platform’ to accelerate growth plans, while MI cited the opportunity to add a strong UK member firm and expanded US representation.

Mark Levenfus, chairman of MI and chairman of Morison KSi, said: ‘Together we have more resources, skills, experience, depth, breadth and reach, but most importantly the merger is built on a shared culture and commitment to working with only the highest quality firms to serve our clients’ international needs.’

Graham Tyler, partner, executive board and head of business development at Kingston Smith in the UK has been named as the vice chairman of Morison KSi.