Legal and General has become on of the largest fund management groups in the world.
It is the largest money manager in the UK.

http://www.legalandgeneralgroup.com

Assets Under Management (AUM) is at £717 Billion.

http://www.legalandgeneralgroup.com/investors/news_releases/releases2015.asp?newsid=260

To grow the business Legal and General has a programme to fund its investment by attacting debt investors.
Institutions who are willing to lend (bond buyers) for a safe and stable return from the Legal and General in this case.

http://www.legalandgeneralgroup.com/investors/debt.html

This is the bond issuance programme, 8 issues. A total debt outstanding of £2,500 Million. That is £2.5 Billion on a business with £717 Billion of assets under management.