I was thinking of enabling BT's parental controls to protect our children.

The reason I have not done so previously is that both my wife and myself login to work using VPNs on our work laptops, and on my home PC I use a paid VPN service to mask my IP address when downloading torrents.

Would the BT parental controls stop these VPNs working? Why is that - because it forces you to use BT DNS servers? Or because it blocks all VPN traffic to avoid users getting round the parental controls?

Many thanks.

I can see it potentially blocking the paid VPN service but if they're blocking work VPNs too that seems a bit ridiculous.

I don't use BT, can you add your work's VPN concentrators as permitted IPs or sites or whatever?

Currently I have not activated BT parental controls at all, and can use any DNS service I want, however, apparently once parental controls are activated, you are forced to use BT DNS servers, all other DNS settings will result in an error message.
Port 53 (DNS) requests are intercepted at network level.
Now I am not sure if my VPN will somehow get round this, by encrypting DNS to them, but I doubt it.
Have I got this wrong?
Thanks.

If you can establish the VPN connection with parental controls turned on, then you will be able to do anything you want. All BT's filter will see is a connection to a VPN provider, it won't see what you are doing through it.

(provided of course that all traffic is configured to go through the VPN - some work VPNs don't do this, it's up to their IT policy)