I agree with most of 1 Valves replies it is the nearest the truth that can be conveyed and easily understood.
This all goes back to the Shawcross report and the implementation of its recommendations. Track racing in the UK became the responsibility of the RAC/ACU under FIM Rules, The ACU contractually devolved the responsibility for managing Speedway to the SCB who in turn authorise the staging of the sport to the BSPA/L under licence. This pyramid provides the security to manage risk and/or litigation from anywhere in the pyramid to the top.
To complicate matters further all organisers and competitors in any motor sport require the protection of the "Off Road Motor Sport" regulations which can only be through a recognised association properly constituted, adequately insured with established racing and racing circuit criteria. There's a bit more to it but basicly racing machines do not have to comply with the road traffic acts and construction and use regulations. Similarly a competitor cannot be prosecuted under those acts for say dangerous driving or overtaking on the inside as examples.
The pyramid has remained intact for decades until Nora came along and set up a compliant model that mirrored the ACU on a smaller scale consequently there was not a strong enough reason to prevent Nora licencing/staging track racing or any other motor sport, they put everything in place.
Now we've all seen the kicking and screaming coming from the bottom of the Pyramid but as long as Nora remain compliant I don't see a way of stopping them as long as they do not call it Speedway racing as that type of racing is legally the responsibility of the ACU in the UK.
NB. The Off Road Motor Sport Regulations work slightly different in Scotland, very often the Police have to attend to verify that it is an off road event.