They were migrated to the BIS platform between [July](http://webarchive.nationalarchives.gov.uk/20110709045438/http://www.insolvency.gov.uk) and [August](http://webarchive.nationalarchives.gov.uk/20110810171347/http://www.insolvency.gov.uk) 2011. 

Our realistic options are 
* Global 410 to the timestamp in 2011
* Global 301 to the organisation homepage on GOV.UK
* Treat as alias to BIS host

Thoughts on our policy here are welcomed - this is a relatively common thing with legacy domains.