Onside Accounting

Who we are

Onside are Chartered Certified Accountants, Business Advisers and Tax Specialists supporting start-up businesses in the UK. We have a passion for supporting start-ups whose accounting needs evolve as they grow.

The company was founded by Martin Brennan, a fellow of the Association of Chartered Certified Accountants (FCCA). Since qualification Martin has spent much of his career working in operational leadership and technical roles in high-growth accounting practices. Martin takes great pride in delivering high standards of work at all times and particularly enjoys developing people, with an excellent track record of converting aspiring young professionals into qualified accountants and tax advisors.

Our Team

Martin Brennan

Founder & CEO

Aideen McCambridge

Operations Director

Ryan Snape

Managing Director,
Onside Tax

Linda Lipkova

Client Manager

Molly Jenkins

Client Manager

Ruta Pullar

Financial Accountant

Lygia Martin

Tax Associate

Alisha Patel

Financial Administrator

Lyden Masella

Financial Administrator

William Grabham

Financial Administrator

Alexandra Isaie

Financial Administrator

Our Vision

Onside's vision is simple. We want to be part of your story and we want you to be part of ours. We want our team and our clients to value what we do and more importantly, we want to enjoy it. 

Our vision is reflected in our values:


Our business is fast-moving and adaptable to change


Our team can work flexibly, around your needs and ours


We are here to work together to support your business


We like to know the people we work with and enjoy it!


We invest a great deal in our people to help them grow

Our Services

Onside offer a vast range of accountancy, tax and other advisory services  - 

Accounting & Tax

Keeping on top of your filing responsibilities with HMRC and Companies House.
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Tax Advisory

Explore our range of Tax Advisory Services.
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R&D Tax Credits

Manage your R&D tax credits application with the help of our expert advisors.
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Onside Accounting is a trading name of Onside Accounting Limited which is registered in England & Wales under Company Registration No. 13428300