In rare cases, a buyout firm can make a strong return on its investment in a company and still see it struggle and fall into administration. This particular quirk of the private equity model is likely to be scrutinised this week in light of the high-profile collapse of phone retailer Phones 4u.

Phones 4u, owned by European buyout firm BC Partners, announced on Monday that it would fall into administration after its contracts with major network operators EE and Vodafone were not renewed.