The present invention relates to a bispecific binding molecule comprising three binding domains, wherein a first and/or a second binding domain are capable of binding to the extracellular 5T4 antigen and the remaining binding domain(s) is (are) capable of binding to the CD3 receptor complex on T cells. Moreover, the invention relates to a nucleic acid sequence encoding fusion protein, a vector comprising said nucleic acid sequence and a host cell transformed or transfected with said vector. Furthermore, the invention relates to a process for the production of the fusion protein of the invention, a medical use of said fusion protein and a kit comprising said fusion protein.