You need an invitation, which can be obtained from tour operators, who will expect you to travel with them. They will also help to obtain visas and will know the latest travel regulations. At least two reliable operators run tours to Libya. Explore Worldwide (0870 3334001, explore.co.uk) offers a five-day visit to Tripolitania and a 15-day trip to the sites of the Roman empire. The Adventure Company (0845 4505311, adventurecompany.co.uk) runs a tour that combines ancient cities and the Ubari sand sea. According to the Foreign & Commonwealth Office website, you need at least £200 cash to enter Libya and can expect severe penalties for possession of alcohol or illegal drugs.
Peter Elliott

Libyan tour company Arkno Tours (020-8855 6373, arkno.com) will tailor everything to suit you.
Rachel DeLisser

Silk Road and Beyond (020-7371 3131, silkroadandbeyond.co.uk/libya.html) offers private tours, and the ones in their website or brochure can be modified to meet your own personal wishes.

Howard Banwell

I can recommend the Roman North Africa tours led by Dr Brian Brennan through the University of Sydney's Centre for Continuing Education (cce.usyd.edu.au).
Jane

If you have advice or questions, email: ask.a.fellow.traveller@theguardian.com.