What to book:
P&O (0843 374 0111; pocruises.com) has a choice of cabins specifically designed for single passengers on six of its eight ships. Of these, Arcadia – which is a mid-size, adults-only vessel – has a small number of inside and balcony single cabins on the sundeck. There are also options on Aurora, Azura, Britannia, Oriana, right, and Ventura. Ships operated by Fred Olsen Cruise Lines (0845 314 2968; fredolsencruises.com) also cater well to solo travellers, with a good choice of single-berth cabins available. Keep an eye out for the latest supplement-free offers published on its website, because these sell especially quickly.