This paper describes recent measurements of the tau lifetime and leptonic branching rations, concentrating on results from DELPHI at LEP but also mentioning results from other experiments, in particular those from other LEP experiments. The DELPHI analysis is based on around 6500 t+tpairs in the barrel region, taken in 1991. The combined LEP results show that the ratio of the tau to muon Fermi coupling constants is consistant with unity. Abstract This paper describes recent measurements of the

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... au lifetime and leptonic branching ratios, concentrating on results from DELPHI at LEP but also mentioning results from other experiments, in particular those from other LEP experiments. The DELPHI analysis is based on around 6500 rt77~ pairs in the barrel region, taken in 1991. The combined LEP results show that the ratio of the tau to muon Fermi coupling constants is consistant with unity.