Can tenant in common remortgage without agreement?

[TutiFrutti]

Just that really, we have a scenario where we believe a tenant in common has remortgaged the property without the knowledge of the other party.
They have been estranged for some time so one party hasn't been living there.

The mortgage will not be effective against the wronged party's interest, although presumably it paid off an existing mortgage so there will be a debt owed by wronged party to the other an the amount of half the old mortgage debt.

It is likely also fraud.

I'm assuming here that the wronged party is also registered proprietor at the land registry.

Property was purchased as tenants in common 50/50, relationship broke down and one party moved out.
Some years later the person who moved out passes away and it is discovered they have been removed as a named party with the land registry after death by the remaining tenant in common.
Further investigation seems to indicate they have either paid nothing off the mortgage for years or it's been remortgaged.
All getting a bit murky.
It is in the hands of a solicitor but I wondered if anyone here had any experience of this.

If they hold the property as a tenant in common then the other proprietor can remove the dead proprietor from the register by lodging proof of death via a DJP form (death of a joint proprietor).

However the form A restriction which was on the register to protect the tenants in common agreement would remain and the land registry should not register a charge/mortgage as capital money would arise.

The living proprietor could have transferred the property to themselves and another party, via a transfer of a share, which if not for value, would be able to be registered and then taken out a charge at a later date which would allow them to be able to register the charge on the property.

Ideally your solicitor needs to get copies of the register and follow the process through to a what's happened to the property in order to establish fraud or land registry error.

It seems the mortgage was taken out some years before the transfer whilst the now deceased party was still alive but apparently without their knowledge.
Another lesson so often seen on these threads, get your affairs in order for the sake of your loved ones!