Using own component within data grid template

I am trying to reach a surrounding component from a a data grid cell component template

  deleteItem(id) {
  render() {
    return html`
      <vaadin-grid .items=${this.items}>
	   <vaadin-grid-column header="item" path="name"></vaadin-grid-column>
          <template class="header">delete item</template>
            <button onclick="${() => this.deleteItem('[[]
              delete [[]

Everything looks fine, i see the columns and the button, but the deleteItem method is never called.
Any idea what I am doing wrong?

The code is a part of a lit-element component

I got this working with the column renderer method, but it would be nice to use the template functionality