Answer by taking a quote from the following article:

Thin Lizzy are a hard rock band formed in Dublin, Ireland in 1969. Two of the founding members, drummer Brian Downey and bass guitarist and lead vocalist Phil Lynott, met while still in school. Lynott led the group throughout their recording career of twelve studio albums, writing most of the material. The singles "Whiskey in the Jar" (a traditional Irish ballad), "Jailbreak", and "The Boys Are Back in Town" were major international hits.

The beginning of 1982 was marred by both Downey and Gorham having to take breaks from the European tour to recover from personal problems. Downey was involved in a fight in a nightclub in Denmark in February, and Gorham was suffering from drug-induced exhaustion. Downey missed five concerts, and was replaced by Mark Nauseef again for three of them, and by Mike Mesbur of support band The Lookalikes for the other two. In March, Gorham collapsed and returned home; eight concerts were performed as a quartet and six others were postponed.  Later in the year, Lynott went on a solo tour and released his second solo album, which did not sell particularly well. Snowy White left the band in August 1982, having tired of the disorganised schedules and Lynott's drug problems, although by his own admission he was too restrained and quiet to fit in well with his more raucous bandmates. White went on to achieve top ten chart success in the UK with his single "Bird of Paradise" in 1983. Long-time co-manager Chris O'Donnell also left at this time, later stating, "A once-brilliant band was turning to crap before my very eyes."  Lynott wanted to find a replacement for White before starting to record the next album, which would turn out to be the band's last. By September 1982, he had settled on John Sykes who had been a member of Tygers of Pan Tang, and he co-wrote the first single from the album, "Cold Sweat", although the rest of the album had already been written. Thunder and Lightning was released in March 1983, and was much more successful than its predecessor, reaching no. 4 in the UK. Sykes' presence had rejuvenated the band musically, the composing credits were evenly shared, and the style had grown much heavier, veering towards heavy metal.  The tour to support the album was to be a farewell tour, although Lynott was not convinced that this would be the end of the band. Sykes wanted to continue, although Gorham had had enough. The tour was successful, and some concerts were recorded to compile a live album. Partway into the tour, many of Thin Lizzy's past guitarists were invited onstage to contribute to some of the songs they had originally recorded, the only exception being Snowy White. The album was released in October 1983 as Life, which included an older performance of "Renegade" featuring White, and reached no. 29 in the UK. The tour continued while two more singles were released, the last of them, "The Sun Goes Down", only reaching no. 52 in August. Lynott also undertook another solo tour, accompanied by Downey and Sykes, under the name of The Three Musketeers.  After a difficult leg of the tour in Japan, where some members of the band had difficulty obtaining heroin, Thin Lizzy played their final UK concert before their break-up at the Reading Festival on 28 August 1983, which was eventually released in 1992 as their BBC Radio One Live in Concert album. The last concert came in Nuremberg on 4 September, at the Monsters of Rock festival, after which the band members went their separate ways.

Who was the lead singer on thunder and lighting?
John Sykes