Who hasn’t yet succumbed to the phenomenon of Downton Abbey? HuffPostUK Entertainment has watched in awe as Julian Fellowes’ period drama – made for ITV! – has taken on all British comers in the ratings battle for Sunday night television, and then wandered off to America to beat home-grown favourites at the Emmy Awards too. What IS the magic ingredient? In Series 1 and 2, there was the will-they-won’t-they romantic suspense of Lady Mary (Michelle Dockery) and Cousin Matthew (Dan Stevens), and Series 3 has seen the ebullient arrival of Shirley Maclaine to keep the Dowager Countess (Dame Maggie Smith) and others on their toes. But that can’t be all. Perhaps, even in our now classless society, we’re suckers for a bit of well-written nostalgia, especially when it’s witty, the lighting and location (Castle Highclere in Berkshire) are all terrific and, even when his wife Cora is refusing to sleep with him, Earl Grantham can still rely on his mother’s love, and his dog’s wagging tail. Guilt-free pleasure to be had by all.