  The goal of the DIRAC experiment at CERN (PS212) is to measure the
$\pi^+\pi^-$ atom lifetime with 10% precision. Such a measurement would yield a
precision of 5% on the value of the $S$-wave $\pi\pi$ scattering lengths
combination $|a_0-a_2|$. Based on part of the collected data we present a first
result on the lifetime, $\tau=[2.91 ^{+0.49}_{-0.62}]\times 10^{-15}$ s, and
discuss the major systematic errors. This lifetime corresponds to
$|a_0-a_2|=0.264 ^{+0.033}_{-0.020} m_{\pi}^{-1}$.
