It's a disgusting and dishonest resignation letter. Attacking all and sundry, taking no responsibility, but above all lying about the process that follows:
// I am now being forced out of parliament by a tiny handful of people ...//
The Committee cannot "force him out": the Commons gets a vote on the report.
// ... without the approval even of Conservative party members ... //
See above. The Commons gets a vote.
// ... let alone the wider electorate. //
A suspension triggers a recall petition, but that only passes if enough constituency members sign it. And there is nothing to then bar Johnson from standing in that election. So the "wider electorate" would absolutely be a part of the process.
So that's three lies, or at least blatant errors, in a single sentence. As for "no evidence", well, that will be laid out in the report for everybody to evaluate, but this is a transparent attempt to undermine that while only he (and his team) can read it.