The British Horseracing Authority (BHA) is the independent body responsible for regulating the sport of horseracing. It works closely with animal charities such as the RSPCA and World Horse Welfare to ensure that the highest of standards are upheld. As a consequence, Britain is regarded as having one of the best regulated racing environments across the world. I am not aware of any current plans to replace the BHA's welfare role with a new body.
It is always upsetting to hear about the death of a horse during a race, but I have been assured that the BHA has a number of policies to ensure that racing is as safe as possible for horses. These include not licencing any racecourse in the UK which is not welfare approved, ensuring all races have veterinary surgeons on hand to administer treatment and investigating any course showing an increase in fatalities. I am encouraged that in the last 20 years horse fatalities during races have fallen by a third, to 0.2 per cent of runners.
I understand your concern about life after racing for these horses. The Retraining of Racehorses is the official charity dealing with the welfare of retired racehorses. It raises funds through regulatory and licence fees from racing, as well as from donations. It runs a nationwide programme find new homes and roles for these horses, including in other recreational activities.