I haven't found any info on this. I learned that I cannot bring assets into an ISA (see e.g. here), but there is no mention anywhere about taking assets out of one. I know the government expects to tax anything coming out of an ISA, but that does not mean I have to incur additional expense connected to sale and repurchase.
The background to this is a letter from Barclays informing me that due to Brexit they cannot continue to provide services because I'm in EU. The investment ISA I have with them holds shares in mutual funds from well-known providers (Blackrock, Janus, etc).
My options, as detailed in the letter, are to either liquidate the ISA or to 'transfer my holdings to another provider'. Could I give them contact details for an Interactive Brokers account in my name (for example)? Or is the 'another provider' supposed to mean another ISA provider (in which case the option does not really make much sense)?