The UK Tested Its Stablecoin Rules With Real Firms. Here’s What Changed | The FCA’s Matthew Long

How do the rules that govern new financial services actually get written? And what happens when a regulator tests them on real products before finalising them?

In this episode of The London Fintech Podcast, Tony Clark is joined by Matthew Long, Director of Payments and Digital Assets at the FCA, to explore how the UK built its crypto and stablecoin regime. They also look at what happened when the regulator tested its proposed stablecoin rules with real firms in a live sandbox.

Matthew, who has led the design of the regime since 2022, explains what the testing revealed and how the final rules changed after consultation and testing.

The changes range from simplifying how backing assets are calculated to making disclosure requirements less prescriptive. He also shares what surprised the regulator about how quickly fintech firms could develop new solutions.

The conversation also covers the opening of the FCA’s authorisation gateway for crypto firms and the early response from applicants. Matthew sets out what firms need to show to be authorised, including clear governance, wind-down plans and strong financial crime controls.

Matthew also discusses how the UK is working with regulators internationally and the upcoming work on decentralised finance and tokenised payments. He explains how the FCA is beginning to examine questions such as liability when AI makes payments, through its supercharged sandbox.

For anyone building, investing in or following the UK’s digital asset market, this is a rare look at how financial regulation is made, tested and changed, and what comes next.

00:00 Trailer & Intro

01:20 How the UK's Crypto Rules Get Written

02:09 The Authorisation Gateway Opens

04:03 Guidance, Timelines and the Market the FCA Wants

06:11 What Counts as a Crypto Firm

07:47 From Registration to Full Authorisation

08:54 Inside the Stablecoin Sandbox

12:08 What Testing Changed in the Final Rules

14:33 What Surprised the Regulator

15:38 What Firms Need to Show to Get Authorised

20:23 Working With Regulators Globally

23:48 What's Next: DeFi, Tokenised Payments and New Payment Rails

29:06 Keeping Up With Fast-Moving Technology

31:38 AI Making Payments and the Supercharged Sandbox

37:39 Advice for Firms Not Yet Involved in Crypto

40:01 The FCA's Mission for the UK Market

43:15 Career Lessons and Life Outside Work