Guest became the 5th Baron Haden-Guest, of Great Saling, in the County of Essex, when his father died in 1996. He succeeded upon the ineligibility of his older half-brother, Anthony Haden-Guest, who was born prior to the marriage of his parents. According to an article in The Guardian, Guest attended the House of Lords regularly until the House of Lords Act 1999 barred most hereditary peers from their seats. In the article Guest remarked: