Is this a case of taken without owners consent (TWOC)?

[PaulaTrilloe]

Sister has returned from Spain to UK back in Feb 2021 reason = no residency so can only spend 6 months in the EU post BREXIT. She's rented a place there for 5 years. My mother offered for her to stay at hers as it appeared to be a temporary low cost solution. I warned mother that it could end in tears as sister can be volatile. Mother is 80, has anxiety and MH issues.
Mum decided to put sister on car insurance

as sister had said she would help mother with errands, doctor visits and shopping

After about 1 month sister gets a job in the next county. Basically takes the car, got a parking ticket, car broken down. Mum pays fine and gets car fixed. Sister has row with mother, storms off taking car. Doesn't return. Apparently sister was sleeping in the car near workplace and/or staying with 'friends'. Refuses to respond to mums calls and texts to return car. As it has now been 8 months and thought the plan was to return to Spain after 6. I asked mother when her MOT is due. Apparently January.
Mother calls me and says sisters insurance has now expired (seems strange as I thought it would run for the term of mothers insurance she was being vague so not sure if this is true!)
Is this a case of Taking Without Owners Consent (TWOC)? Or is it something else?
I have tried to contact my sister who also does not return my calls or texts. Have suggested mother writes a letter to CF sister via her workplace in the absence of any other known address to demand return of car and to inform her of insurance situation. Any suggestions?

Yeh I’d say it’s twoc, it’s not her car, consent has been withdrawn. Personally I’d ring the police

I think it’s not that straightforward-if she’s on the insurance that’s implying consent

Being on the insurance is not implying consent. It means she is insured to drive WHEN CONSENT IS GIVEN.
OP, she absolutely should call the police.

You are insured to drive with permission of the owner… no permission no insurance. Your DM is the registered keeper, she’s the owner, it’s her car.

Your mum will need to show that she wants the car back, so some written recorded communication to your sister making it clear the car must be returned immediately and she has removed her from the insurance policy. If it’s not returned then it would be stolen/TWOC. It might be worth spending money on getting a solicitor to advise and send the correspondence to your sister if the car is worth it.

Thank you for your advice and the need for written proof of wanting the car back. I had asked mum whether she knew where the car might be located. She thinks it is in a small village (about 60 miles away in the next county). Even if someone gave her a lift there to collect it she doubts she could drive it back (she does have a spare key).
The fact that my sister is in denial and ignoring our messages isn't helping.
I can understand she may not want to create a legal issue format sister but any escalation might make that happen.
Would welcome creative ideas to locate the car before going down the Police / ANPR route. Mum confessed to me that sister had 'borrowed' the keys and car when mum was asleep and sister was 15 and had got stopped by police. (I never knew this it was 30 years ago!). Sister certainly has form for impulsive and compulsive acts. BTW i don't drive and I live 300 miles away

Personally, I wouldn’t wait on contacting the police. Your mum has already texted your sister asking for the return of the car. That is evidence she has withdrawn permission.

If DD isn’t insured DO NOT ask her to return the car as that is giving her permission to drive it. If the sister is no longer insured and is driving the car, if there were consent there then your mother would be guilty of allowing a car to be driven without insurance.

If your mum doesn’t want to risk branding her DD a criminal she should text again telling her DD she isn’t insured anymore and must not drive the car. Ask her to immediately return keys (do not ask her to return the car itself) and give the car’s location. But if there’s no immediate response she’s probably going to have to go to the police soon to ensure her own insurance coverage will payout for any recovery or damage etc.