How safe are private pensions?
If the company goes tits up will the government step in?
Depends what it's invested in.
The 'big' company (like Prudential, Standard Life, Liverpool Victoria, Hargreves Landsdown, whoever) who 'supply' the pension (called the wrapper) hold your assets in a separate account to their own money. They cannot access your assets without your agreement, and if they went belly up your assets would be ring-fenced from their creditors. If one of the really big boys went bust (Prudential for example) then you'd probably be better off worrying about stocking up on Baked Beans and shotgun shells because the world would be coming to an end anyway.
You (or your advisor) choose which assets to hold within the pension 'wrapper'. You can invest in millions of things - individual companies, unit trusts, OEICS, Gold, Storage pods, airport parking spaces, cheese shops on the moon, whatever. If you invest the whole lot in one company, say Poly Peck or Northern Rock, and that company goes belly up, then you will lose the lot. If you invest your money across a range of different assets - say 10-20 different companies - then if one goes belly up you've only lost a portion of your assets/money.
You can invest in tracker funds which basically buy a bit of every company in the market they're tracking (FTSE100, FTSE250, All share, US, Europe, Global, whatever). Or you can invest in managed funds, where a fund manager attempts to pick 20-100 different companies that he/she thinks will out perform the rest of their peers. You pay higher charges for using managed funds, but hopefully they'll perform better than simple trackers. Some do, some don't.
If the company managing your tracker or managed fund goes bust, then again 'your' assets are ring fenced from the companies remaining assets. If one of the companies held in the fund goes bust then you would lose any money associated with that company, but the rest will be safe.