What does the SDP’s story tell us about now?

I’ve recently been reading Anthony King and Ivor Crewe’s history of the SDP and it got me thinking about the possible lessons the SDP has for anyone who wanted to try and set up a new party in the centre and/or create a new party as a centrist split group from the Labour party. I don’t think ‘the SDP failed, therefore any split now from Labour would also fail’ is an argument with much strength but I think it’s worth understanding why it happened and why it failed before we go insisting that there are direct parallels between it and what’s happening now.