Onside Accounting and Onside Tax donate 5% of all profits to charities chosen by their employees
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.

In 2024, Onside were awarded Approved Employer status from the ACCA. The ACCA Approved Employer Programme recognised Onside’ high standards of staff training and development, which show Onside’s commitment to ensuring all our ACCA members and trainees have the right skills, ethics and competences to add value and drive the business forward. 

Our Team

Martin Brennan

Founder & CEO

Aideen McCambridge

Operations Director

Ryan Snape

Managing Director,
Onside Tax

Molly Jenkins

Head of Client Services

Linda Lipkova

Client Manager

Lewis Humphries

Client Manager

Gemma Scott

Finance Manager

Robert Hadden

Personal Tax Manager

Seamus Duffy

Financial Accountant

Alisha Parker

Financial Accountant

Audrone Urbonaite-Melas

Financial Accountant

Anna Maria Parri

Financial Accountant

Alisha Patel

Senior Financial Administrator

Calum McCarthy

Senior Financial Administrator

Luke Maneely

Senior Financial Administrator

Lygia Martin

Tax Associate

Jemma Mason

Tax Associate

Alexandra Isaie

Financial Administrator

William Grabham

Financial Administrator

Lyden Masella

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:

Dynamic

Our business is fast-moving and adaptable to change

Flexible

Our team can work flexibly, around your needs and ours

Collaborative

We are here to work together to support your business

Personal

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

Growth

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