Near Miss of the Day 476: Learner driver pulls onto roundabout in front of cyclist

The other sites I found all say that 'you are deemed to be in control of the car when you are supervising a learner driver'

https://www.4youngdrivers.co.uk/information/rules-for-supervising-learne...

https://www.adrianflux.co.uk/learner-drivers/guides/supervising-learner-...

Why else there be a requirement that

Anyone you practise your driving with (without paying them) must:

be over 21
be qualified to drive the type of vehicle you want to learn in, for example they must have a manual car licence if they’re supervising you in a manual car
have had their full driving licence for 3 years

There are legal responsibilities when supervising learners but they do not extend beyond the rules which apply to aiding, abetting, counselling, and procuring a crime or offence.  What this means in the context of driver supervision is that for the supervisor to be prosecuted they have to do something or omit something on a fairly large scale.  In criminal cases (theft, robbery etc) rather than statutory ones (traffic offences etc) consideration is given to the notion of 'guilty intention' under the Latin expression 'mens rea'.  So if the person didn't mean to commit the crime they are unlikely to be convicted.  
For the purposes of driving supervision if a learner was approaching a traffic light and the supervisor was recorded on a dash cam telling the driver to slow down on approach but the learner chose not to do so and went through as the light changed to red (assuming no dual controls) then it would be hard to prove the supervisor hadn't fulfilled their obligations to supervise the learner and they would not be charged.

Consider the fact that it was made illegal in the 1960's for training cars to have an accelerator and only a secondary brake and a clutch can be fitted.

In response to your query; I have no idea why various websites make the comments they do. There are 46,000 driving instructors in the UK and a large majority have websites to attract customers.  Some feel it useful to copy comments they see elsewhere, perhaps to look more professional.  However the most unambiguous way to quote legislation in the UK is to quote the outcome of statutes as they are written or the decisions made not by the lower courts but by the courts of appeal in England and Scotland.  Hope this is of interest to you.

Thanks, so a bit more nuanced than I was lead to believe.

Why should the driver make allowances for the cyclist? As an incoming piece of traffic, the cyclist must act accordingly.

What does that even mean? Both parties were 'incoming traffic' - that's kind of in the nature of a junction.

The legislation and Highway Code advice may be ambiguous and confusing, but the convention (which is the only way that roundabouts of this size really work) it's that you give way to any traffic approaching from the right, regardless of whether they have entered the roundabout. That's why you occasionally get the 'deadlock' situation where you'll get people at each of the entrances, all giving way to the one to the right, and no-one moving. That results in occasional awkwardness, but it's clearly better than them all pushing straight in at the same time because 'they haven't entered the roundabout yet'.

It would have been considerate of the bike rider to moderate their speed as they approached, even if they believed that they could see that the way was clear for them, thereby allowing both parties to maintain their progress without problems. Given that they didn't, though, the driver should have seen them coming and given way.

As I said though, I wouldn't particularly blame what appeared to be a very tentative learner driver, who probably wasn't yet able to judge their ability to complete their entry and begin circulating at a normal speed before the bike rider got there. However, the instructor should have been more aware that this was likely to happen and stopped them. And they certainly should have stopped them from driving on after the incident, when they were likely to still be panicked and not in full control (As seems to be evidenced by the fact that they had another near collision as they drove away).