FOREXVOX, London, United Kingdom

ForexVox, based in the City of London, has been created by traders for traders.
FCA UK regulated

UK Member of FSCS (Financial Services Compensation Scheme) with deposits up to GBP £85,000 per person protected. High-speed execution, customized price feeds, system reliability, and tight pricing.

CRESCO FX, London, United Kingdom

CrescoFX was founded in 2011 by engineer-turned-entrepreneur Derek Mayne.
FCA UK regulated

As a boutique FX broker, CrescoFX was designed to serve professional traders seeking a reliable and competitive client-centred alternative to traditional liquidity providers. The company grew initially through word-of-mouth and referrals through existing clients and now has operations in several international locations.

VARIANSE UK, London, United Kingdom

Pure STP broker model. Direct connectivity to Tier 1 banks, Non-Bank and High-Frequency Liquidity
FCA UK regulated

Varianse UK provides retail and institutional traders deep interbank liquidity, razor-sharp pricing, and best-in-class technology for strategy building, order routing, and low latency execution.

UltraFX VPS

Collocated to the major liquidity providers, exchanges and interbank dealing servers.
http://www.ultrafxvps.com

UltraFX offers collocated virtual and dedicated servers with ultra-low latency connectivity, serving proprietary trading firms, investment banks, hedge funds and individual algorithmic traders to access various trading venues and networks from Equinix LD4 (UK) and Equinix NY4 (US) data center.