Our Story

Diamond & Skillen is a Chartered Accountants Practice situated at 89/101 Royal Avenue in the centre of Belfast.

We are affiliated to the institute of Chartered Accountants in Ireland (ICAI), also known as Chartered Accountants Ireland (CAI)


Originally formed in 1926 by P Oswald Diamond, the practice operated from offices at 5 Bedford Street, Belfast, moving to 58 Howard Street in Belfast in 1965.  In 2002 we moved to our current prestigious premises on Royal Avenue.


1926 - 1961:  Sole practitioner: P. Oswald Diamond FCA

1961 - 1965:  Partnership: P. Oswald Diamond FCA and Victor E. Skillen FCA

1965 - 2001:  Sole practitioner: Victor E. Skillen FCA

2001 - date:  Sole practitioner: Nigel V. Skillen FCA

Meet the Team

Nigel V. Skillen FCA      Joined the practice in 1987

J. Nelson Dillon            Joined the practice in 1969

Colin E. Skillen             Joined the practice in 1998

Nigel Skillen

Chartered Accountant

Nigel is responsible for all audit work undertaken by the practice. He also undertakes all business, corporate and individual taxation work - both day-to-day compliance and planning aspects. He was responsible for updating all of the practice's systems and policies, and has ensured that Diamond & Skillen are among the leaders in independent accountancy practices in terms of utilisation of I.T. and ground breaking software applications. He has extensive experience in all UK taxes (income tax, corporation tax, capital gains tax, inheritance tax, stamp duty / SDLT and Value Added Tax) and is willing to quickly give detailed advice to clients when required.

Nelson Dillon


Nelson is responsible for the Book-keeping services and VAT compliance work of the practice. He has great experience in these fields and has a wealth of knowledge which is of use to all of our clients.

Colin Skillen


Colin is responsible for the payroll bureau and "Human Resource" consultancy work of the practice. He also undertakes book-keeping bureau work. Having worked as a management accountant in a large firm, he has a good knowledge of the workings of bigger industry and the requirements of various funding organisations. He also has extensive experience in the voluntary sector, being on the Board of a local Primary School and also Townsend Enterprise Park.

Next Steps...

Please get in contact to discuss how we can assist you.