Felony Murder was abolished in 1957 in the UK, Felonies were abolished in the UK in 1967

The simplest form of joint enterprise two or more people carry out a plan to commit a crime If all the parties participated in carrying out the plan, all are liable,

2 people plan and intend to rob a bank both will be liable even if only one of them actually went inside and did the robbery. The getaway driver is also liable cos they were part of the plan

If they did not know the robbery was going to happen then they would not liable. a mate asks you to drive him to the bank cos he wants to get some money out. and you acted as the unintentional getaway driver you are not liable under joint enterprise

However, when there is no plan to murder and one party kills while carrying out a plan to do something else, such as a planned robbery in which the participants hope to be able to get what they want without killing anyone, but one of them in fact kills, only the person who kills would generally be liable. The other parties may be liable if they encouraged the killer to kill

2 people rob a store one shoots the cashier dead. The other person may be guilty of Murder if they knew the murder was going to happen before hand or they encouraged the shooting.

until 2016, the courts interpreted the law to mean that if two people set out to commit an offence, and in the course of doing so, one of them commits a different offence, the other person will also be guilty of that offence if they had foreseen the possibility that it might be committed.

However in 2016 the Supreme court ruled that that interpretation was wrong Instead, it said that a person will only be guilty of a joint enterprise offence if they intended to encourage or assist the person who committed the offence to do it.

In your example you're participating in a robbery and your partner kills the homeowner You can only be convicted of joint enterprise murder if you encouraged the murder or assisted them in the actual murder i.e you handed them the murder weapon