(1/1) MethodNotAllowedHttpException in RouteCollection.php (line 251)

Boa tarde !!! Criei a classe LoginController e form_login_blade na hora de executa na url localhost:8000\login aparece essa mensagem de erro : (1/1) MethodNotAllowedHttpException in RouteCollection.php (line 251)

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class LoginController extends Controller {

    public function form() {
         return view('form_login');
    }
}

@extends('principal')

@section('conteudo')

<h1>Novo produto</h1>

<div class="alert alert-danger">
<ul>
    @foreach($errors->all() as $error)
    <li>{{$error}}</li>
</ul>

@endforeach
</div>

<form action="/login" method="post">

<input type="hidden" name="_token" value=" {{ csrf_token() }}"/>

<div class="form-group">
<label>Email</label>
<input name="email" class="form-control"/>
</div>

<div class="form-group">
<label>Senha</label>
<input type="password" name="password" class="form-control"/>
</div>

<button class="btn btn-primary" type="submit">Adicionar</button>


</form>

Route::post('/login', 'LoginController@form');